This is a study conducted in a laboratory at the university as a simulation to see the effect of new fiber PMD for different distances. This is done to compare the performance of the digital system with optical fiber WDM. In this simulation are not included remission, chromatic dispersion and nonlinear effects. In this way all of the signal distortions caused only by different combinations of PDM. Polarization effects are very important in communications systems with optical fiber. Optical fiber that is used mainly during the simulation is a standard single mode fiber (SSMF).
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document provides an overview of wavelength division multiplexing (WDM) network design and optimization. It discusses integer linear programming (ILP) as an approach for solving WDM network design problems. The document outlines key concepts in WDM network design, including logical and physical topologies, traffic requirements, and constraints. It also covers different cost functions and formulations that can be used for optimization, including flow formulation and route formulation. The integer linear programming approach allows for finding optimal solutions but has limitations due to computational complexity for large networks. Heuristic methods provide alternatives for more realistic problem sizes.
Dense wavelength division multiplexing....Arif Ahmed
The document discusses performance analysis of dense wavelength division multiplexing (DWDM) optical transmission systems. It begins with an introduction to DWDM, which allows transmission of up to 132 wavelengths over a single fiber. Section 2 provides an overview of optical fiber transmission and prior multiplexing techniques such as time division, frequency division, subcarrier, and coarse and dense wavelength division multiplexing. Section 3 indicates that the performance of DWDM will be analyzed using its application in NEMO, ANTARES, and KM3NeT underwater neutrino telescope experiments.
Simulation of Few Mode Fiber Communication System Using Adaptive Recursive le...rahulmonikasharma
The document summarizes research on simulation of few mode fiber communication systems using adaptive algorithms. It discusses using the recursive least squares (RLS) algorithm to improve convergence speed but with increased complexity compared to frequency domain least mean square (FD-LMS) algorithms. The FD-LMS algorithm is used as a reference. A step size controller is also proposed to improve convergence behavior. Previous studies on adaptive frequency domain equalization schemes and use of normalized frequency domain adaptive filters to increase convergence speed over long transmission distances are also summarized.
Radio over fiber system based on a hybrid link for next generation of optical...IJECEIAES
Radio over fiber technology will play an important role in solving problems facing wireless technology. Envisaging a global village, people could transmit and receive “anytime, anywhere, and anything”. In addition, the explosive growth in internet applications such as the World Wide Web, demonstrates the tremendous increase in bandwidth and low power that the coming world of multimedia interactive applications will require from future networks. ROF technology uses multicarrier modulation like orthogonal frequency division multiplexing (OFDM), which provides an opportunity of having an increased in bandwidth together with an affordable cost and this idea has recently become a suitable topic for many research works. On the other hand, SAC-OCDMA (Spectral Amplitude Coding Optical Code Division Multiple Access) technique is able to enhance the data rate of system and increase the number of user. In this paper we introduce a ROF link using a hybrid OFDM/SAC-OCDMA technique.
techInvestigations with mode division multiplexed transmissionelelijjournal
This article presents proposed topology for mode division multiplexed link with SPDML and VCSEL, modulate electrical signal of 820nm wavelength. Transmission performance has been investigated for numerous modes, bit rates (2.5 to 10Gbps), transmission lengths of MMF (1 to 100km) and attenuation factor in conjunction with parabolic operational mode. Results illustrated successful performance up to nine modes in mode-division multiplexed transmission. Performance is improved at low data rates, illustrated higher OSNR with lower BER,-5dB attenuation factor. Though, at higher bit rate and longer
transmission length received OSNR is unsteady. It further inferred that transmission with large number of multiplexed modes result in degraded performance, augmented with minimization of mode coupling losses.Mode division multiplexed multimode optical communication can be a viable option for supplementary capacity augment in the preexisting and future fiber optic communication links.
DYNAMIC OPTIMIZATION OF OVERLAP-AND-ADD LENGTH OVER MIMO MBOFDM SYSTEM BASED ...ijwmn
An important role performed by Zero Padding (ZP) in multi-band OFDM (MB-OFDM) System. This role
show for low-complexity in résistance against multipath interference by reducing inter-carrier interference
(ICI) and eliminating the inter-symbol interference (ISI) Also, zero-padded suffix can be used to eliminate
ripples in the power spectral density in order to conform to FCC requirements. At the receiver of MB-OFDM system needs to use of a technique called as overlap-and-add (OLA). Which maintain the circular convolution property and take the multipath energy of the channel.In this paper, we proposed a method of performing overlap-and-add length for zero padded suffixes. Then,we studied the effect of this method, dynamic optimization of overlap-and-add (OLA) equalization, on the performance of MIMO MBOFDM system on Bit Error Rate (BER) with AWGN channel and SalehValenzuela (S-V) Multipath channel Model.In the dynamic optimization OLA, the Length of ZP depends on length of channel impulse response (CIR).
These measures, based on SNR, insert the ZP according to the measurement.Dynamic optimization of length of ZP improves the Performance of MIMO MBOFDM system. In fact wedeveloped a technique to select the length of ZP as function of SNR and CIR estimate. In our simulation
this technique improve to 0.6 dB at BER=10-2 with a multipath channels CM4
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document provides an overview of wavelength division multiplexing (WDM) network design and optimization. It discusses integer linear programming (ILP) as an approach for solving WDM network design problems. The document outlines key concepts in WDM network design, including logical and physical topologies, traffic requirements, and constraints. It also covers different cost functions and formulations that can be used for optimization, including flow formulation and route formulation. The integer linear programming approach allows for finding optimal solutions but has limitations due to computational complexity for large networks. Heuristic methods provide alternatives for more realistic problem sizes.
Dense wavelength division multiplexing....Arif Ahmed
The document discusses performance analysis of dense wavelength division multiplexing (DWDM) optical transmission systems. It begins with an introduction to DWDM, which allows transmission of up to 132 wavelengths over a single fiber. Section 2 provides an overview of optical fiber transmission and prior multiplexing techniques such as time division, frequency division, subcarrier, and coarse and dense wavelength division multiplexing. Section 3 indicates that the performance of DWDM will be analyzed using its application in NEMO, ANTARES, and KM3NeT underwater neutrino telescope experiments.
Simulation of Few Mode Fiber Communication System Using Adaptive Recursive le...rahulmonikasharma
The document summarizes research on simulation of few mode fiber communication systems using adaptive algorithms. It discusses using the recursive least squares (RLS) algorithm to improve convergence speed but with increased complexity compared to frequency domain least mean square (FD-LMS) algorithms. The FD-LMS algorithm is used as a reference. A step size controller is also proposed to improve convergence behavior. Previous studies on adaptive frequency domain equalization schemes and use of normalized frequency domain adaptive filters to increase convergence speed over long transmission distances are also summarized.
Radio over fiber system based on a hybrid link for next generation of optical...IJECEIAES
Radio over fiber technology will play an important role in solving problems facing wireless technology. Envisaging a global village, people could transmit and receive “anytime, anywhere, and anything”. In addition, the explosive growth in internet applications such as the World Wide Web, demonstrates the tremendous increase in bandwidth and low power that the coming world of multimedia interactive applications will require from future networks. ROF technology uses multicarrier modulation like orthogonal frequency division multiplexing (OFDM), which provides an opportunity of having an increased in bandwidth together with an affordable cost and this idea has recently become a suitable topic for many research works. On the other hand, SAC-OCDMA (Spectral Amplitude Coding Optical Code Division Multiple Access) technique is able to enhance the data rate of system and increase the number of user. In this paper we introduce a ROF link using a hybrid OFDM/SAC-OCDMA technique.
techInvestigations with mode division multiplexed transmissionelelijjournal
This article presents proposed topology for mode division multiplexed link with SPDML and VCSEL, modulate electrical signal of 820nm wavelength. Transmission performance has been investigated for numerous modes, bit rates (2.5 to 10Gbps), transmission lengths of MMF (1 to 100km) and attenuation factor in conjunction with parabolic operational mode. Results illustrated successful performance up to nine modes in mode-division multiplexed transmission. Performance is improved at low data rates, illustrated higher OSNR with lower BER,-5dB attenuation factor. Though, at higher bit rate and longer
transmission length received OSNR is unsteady. It further inferred that transmission with large number of multiplexed modes result in degraded performance, augmented with minimization of mode coupling losses.Mode division multiplexed multimode optical communication can be a viable option for supplementary capacity augment in the preexisting and future fiber optic communication links.
DYNAMIC OPTIMIZATION OF OVERLAP-AND-ADD LENGTH OVER MIMO MBOFDM SYSTEM BASED ...ijwmn
An important role performed by Zero Padding (ZP) in multi-band OFDM (MB-OFDM) System. This role
show for low-complexity in résistance against multipath interference by reducing inter-carrier interference
(ICI) and eliminating the inter-symbol interference (ISI) Also, zero-padded suffix can be used to eliminate
ripples in the power spectral density in order to conform to FCC requirements. At the receiver of MB-OFDM system needs to use of a technique called as overlap-and-add (OLA). Which maintain the circular convolution property and take the multipath energy of the channel.In this paper, we proposed a method of performing overlap-and-add length for zero padded suffixes. Then,we studied the effect of this method, dynamic optimization of overlap-and-add (OLA) equalization, on the performance of MIMO MBOFDM system on Bit Error Rate (BER) with AWGN channel and SalehValenzuela (S-V) Multipath channel Model.In the dynamic optimization OLA, the Length of ZP depends on length of channel impulse response (CIR).
These measures, based on SNR, insert the ZP according to the measurement.Dynamic optimization of length of ZP improves the Performance of MIMO MBOFDM system. In fact wedeveloped a technique to select the length of ZP as function of SNR and CIR estimate. In our simulation
this technique improve to 0.6 dB at BER=10-2 with a multipath channels CM4
This document discusses wavelength assignment algorithms in WDM optical networks. It compares the random wavelength assignment algorithm to the first-fit algorithm in terms of blocking probability. Blocking probability is lower with the first-fit algorithm compared to the random algorithm. The document also examines the impact of wavelength conversion capabilities (no conversion, partial conversion, and full conversion) on blocking probability. Blocking probability is lowest when full wavelength conversion is possible. The first-fit algorithm performs better than random assignment even without wavelength conversion capabilities.
DWDM is a fiber optic transmission technique that uses different wavelengths of light to transmit multiple data signals simultaneously over the same fiber. This allows network capacity to be dramatically increased to meet rapidly growing bandwidth demands. DWDM provides a flexible solution to fiber exhaust and allows different data formats like IP, ATM, and SONET to be transported over a single optical network. By assigning each signal a unique wavelength, DWDM can multiply the capacity of existing fiber infrastructure.
Enhancing the Data Transmission Capability on Optical Fiber Communication Lin...IOSRJECE
This document discusses methods for enhancing data transmission capability on optical fiber communication links by overcoming dispersion. Dispersion limits the performance of optical communication systems in terms of high-speed data transmission. The document examines different dispersion compensation techniques including chirped fiber gratings, dispersion compensation fibers, and self-phase modulation resulting from Kerr nonlinearity. Chirped fiber gratings introduce varying delays to different wavelengths to counteract pulse broadening from group velocity dispersion. Dispersion compensation fibers with high negative dispersion are used to offset the positive dispersion of standard fibers. Self-phase modulation from optical fiber nonlinearity can also balance the negative frequency chirp from anomalous dispersion, allowing solitons to propagate without broadening. These dispersion compensation methods aim to
1) The document discusses channel estimation techniques for 4G wireless networks using OFDM modulation.
2) Channel estimation is important for coherent detection and diversity techniques in wireless systems, which have time-varying channels. Accurate channel estimation allows techniques like maximal ratio combining.
3) OFDM divides the channel into multiple sub-carriers to combat multipath fading and make channel equalization easier compared to single carrier systems. Channel estimation is needed to characterize the time-varying frequency response of the wireless channel.
This document provides an overview of basic WDM optical networks. It describes WDM as a multiplexing technique that allows multiple wavelengths to be transmitted over the same fiber. There are two main architectures: broadcast and select, which uses a simple star topology, and wavelength routed, which establishes light paths between nodes using the same wavelength. The document outlines the key components and working principles of each architecture, including their advantages and disadvantages. Wavelength routed networks allow for wavelength reuse but require efficient wavelength assignment to avoid bandwidth loss.
RECONFIGURABLE OPTICAL ADD AND DROP MULTIPLEXERS A REVIEWecijjournal
Optical multiplexing is the key function of a WDM network and reliable method for data transport networks. WDM networks configured as rings/mesh along with Optical Add-Drop Multiplexers supports added flexibility, simplicity and augment the spectral efficiency. Further enhancement achieved with Reconfigurable OADM architectures, growing briskly along with automatic network management, let the transport network to acclimatize with dynamically varying environment and flexibly respond to the transport network changes. It permits single or many wavelengths to be added and/or dropped from a
transport fiber without optical-to-electrical-to-optical domain translation. Presently ROADM technology
has revolutionized optical networking and an inseparable part of modern optical communication offering huge bandwidth for data transport at minimum expense. In this view the article presents comprehensive study for numerous generations of ROADM and their architecture and persistent development
IRJET- Design & Performance Analysis of MIMO-FSO Communication System Bas...IRJET Journal
The document summarizes a study on a MIMO-FSO (multiple-input multiple-output free-space optical) communication system using spectrum slicing wavelength division multiplexing (SS-WDM) technique. The system was tested with 4 channels at data rates up to 10Gb/s. The wavelengths ranged from 1550.11nm to 1552.52nm. The results showed the SS-WDM MIMO-FSO system was able to transmit data over 2.5 kilometers with a bit error rate of less than 10-9, even with atmospheric attenuation. The SS-WDM approach improved system performance under different weather conditions compared to non-sliced systems.
Performance Analysis of OFDM in Combating Multipath FadingIOSR Journals
Mobile Communication system has been on high rampage for high data transmission over wireless
medium with various challenges caused by the transmission Channel. OFDM is been discovered in recent years
to deal with this problems because of its ability to elegantly cope with multipath interference. This paper
investigates the performance of different modulation schemes using M-ary Phase Shift Keying (M-PSK) and Mary
Quadrature Amplitude Modulation (M-QAM) in information transmission with OFDM technique over Ideal
channel AWGN and worst channel Rayleigh Fading channel in terms of Bits Error Rate (BER). Analysis was
made for different types of modulation schemes BPSK, QPSK, 4-QAM and 16-QAM gray coded bit mapping.
Also, a feasibility of OFDM been used to combat multipath fading was analyzed with comparison between a
single carrier technique and OFDM multicarrier technique. Variation between SNR results with respect to BER
is plotted to show the trade off differences between the modulation schemes with the result showing that OFDM
allows data transmission with minimal error over fading channel than a Single Carrier
This document provides an overview of Dense Wavelength Division Multiplexing (DWDM) technology. It discusses key topics such as optical transmission, DWDM components like multiplexers/demultiplexers and amplifiers, DWDM networks and topologies, and transmission quality parameters. The presentation contains 32 slides and is intended to briefly explain DWDM as a means of achieving effective fiber-optic transmission and increasing bandwidth.
The document discusses recent advances in optical network technology, including components such as wavelength division multiplexing (WDM) systems, optical cross-connects, and optical switching technologies like MEMS. It outlines commercially available high-capacity optical systems providing terabits per second of capacity, as well as experimental WDM systems demonstrating multi-terabit capacities over long transmission distances. Emerging next generation optical networks are envisioned to be transparent, dynamic, and have switching at the wavelength level.
An important role performed by Zero Padding (ZP) in multi-band OFDM (MB-OFDM) System.
This role show for low-complexity in résistance against multipath interference by reducing
inter-carrier interference (ICI) and eliminating the inter-symbol interference (ISI) Also, zeropadded
suffix can be used to eliminate ripples in the power spectral density in order to conform
to FCC requirements.
At the receiver of MB-OFDM system needs to use of a technique called as overlap-and-add
(OLA). Which maintain the circular convolution property and take the multipath energy of the
channel.
In this paper, we proposed a method of performing overlap-and-add length for zero padded
suffixes. Then, we studied the effect of this method, dynamic optimization of overlap-and-add
(OLA) equalization, on the performance of MBOFDM system on Bit Error Rate (BER) with
AWGN channel and Saleh-Valenzuela (S-V) Multipath channel Model.
In the dynamic optimization OLA, the Length of ZP depends on length of channel impulse
response (CIR). These measures, based on SNR, insert the ZP according to the measurement.
Dynamic optimization of length of ZP improves the Performance of MBOFDM system. In fact
we developed a technique to select the length of ZP as function of SNR and CIR
estimate(repetition). In our simulation this technique improve to 3 dB at BER=10-2 with a
multipath channels CM4.
Dense wavelength division multiplexing (DWDM) is a fiber optic transmission technique that employs light wavelengths to transmit data parallel-by-bit or serial-by-character. It allows for increased fiber capacity and scalability. DWDM evolved from earlier WDM techniques and can transmit 64 or more channels through a single fiber using spacing between 25-50 GHz. Ongoing research focuses on reducing dispersion and developing tunable lasers. DWDM provides a robust, simple, and cost-effective solution for growing bandwidth demands.
International Journal of Computational Engineering Research(IJCER) ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
About Quality of Optical Channels in Wavelength Division Multiplexing Systems...TELKOMNIKA JOURNAL
Researches and the analysis of factors of the systems influencing quality with division according to radiation wavelength are given in article. Especially the communication quality in systems with wave division of channels is influenced by hindrances from Four Wave Mixing. In this regard the technique of definition of number of products of nonlinear effect of Four Wave Mixing getting to ranges of working channels, results of calculation of combinational products for the different number of channels in systems with division according to radiation wavelength is given. Power of a hindrance of Four Wave Mixing in systems with wave division of channels is calculated. Methods of reduction of influences of these nonlinear effects are considered. Conclusions and recommendations on ensuring quality of optical channels are provided in systems with wave division.
Request 100 g webcast presentation-june9_finaldodesimo
Alcatel-Lucent has commercially launched next generation 100G coherent technology in their 1830 Photonic Service Switch (PSS). This provides the highest density of 100G with up to 5x100G per shelf or 15x100G per bay. It offers best-in-class performance through integrated ultra fast electro-optics and Bell Labs innovation. Softbank Telecom has selected this solution to upgrade their Japanese backbone network to support increasing bandwidth demands.
This document discusses dispersion compensation techniques for optical code division multiple access (OCDMA) systems using dispersion compensation fiber (DCF) and fiber gratings. It compares the performance of an 8-user OCDMA system using DCF versus fiber gratings. The results show that DCF more effectively compensates for dispersion, as evidenced by a lower bit error rate and higher Q factor, making it a better dispersion compensation method for OCDMA systems compared to fiber gratings.
Application WDM(wavelength division multiplexing) For COMPSEPatel Ankit
This document discusses the application of wavelength division multiplexing (WDM) in three contexts:
1) Fibre optics, where WDM is used to transmit multiple high-speed digital data streams over a single optical fibre by assigning each stream a dedicated wavelength of light.
2) Aircraft applications, where WDM can enable future aircraft networks that have high capacity, flexibility, security and low cost.
3) RF avionics, where WDM transmission of RF signals over optical fibre has advantages over coaxial cable by offering higher bandwidth and immunity to electromagnetic interference.
Isolation and characterisation of Nitrogen Fixing Bacteria ( Azotobacter Sp.)...inventionjournals
Different strains of Azotobactersp were isolated and charaterised morphologically, folowing their resistance activities against antibiotic and Nacl from Dooars and Darjeeling region of North Bengal.The soil sample studied were DS-1, DS-2 and DJ-1. DS-1 have 50 isolates, DS-2 have 45 isolates and DJ-1 have 50 isolates. Among morphlogical parameter colony colour, shape and size has been considered for this study. Most of the colony are white many shows colour, circular, colony diameter ranges from 1-4.5 cm . Four strains namely DS-1-18, DS-1-25,DS-2-10,DJ-1-45 shows resistance against anibiotic 35mg/l). Nacl tolerance activities of seveteen promising clone has studied, among them three strains namely DS-1-16, DS-1-17and DS- 2-18 shows salt tolerance of upto 4.5%.Nitrogen fixing capacityof five strains has been carried out for highest antibiotic resistance starins, among them DS-2-10 shows maximum N2 content (0.006 %)
Performance Evaluation of Thermoelectric Materials: A Case Study of Orthorhom...inventionjournals
Designers often face the predicament of non-standardized and poor performing materials for thermoelectric module manufacturing. Other than analytical means, the only method to evaluate the performance of thermoelectric materials would be through experimental means. This work studies the experimental approach employed in performance investigation of thermoelectric materials using Orthorhombic SnSe crystals as a case study. The result obtained reveals the high thermoelectric conversion efficiency of orthorhombic crystals, and that they can operate as both low and high temperature thermoelectric material.
Optimization of Coal Blending to Reduce Production Cost and Increase Energy E...inventionjournals
The productivity level of the electricity production is an important indicator in the power plant efficiency. A chase study in this research was choosen at coal power plant PT PJB UP Paiton which is the productivity level of the generated electricity decreases until below the production target level. It due to several factors such as quality of coal and plant design. Depletion of coal heating value (low rank coal) reduce total amount of enerated heat in boiler and finally increase unburned carbon, plant inefficiency, as well as the high production cost. On the other hand, utilizing the high rank coal cause more expensive price. Therefore, the optimiation of coal blending to obtain more plant efficiency and lower production cost is required. This research focus on optimization of low and high rank coal blending that can decrease the production cost and increase plat efficiency. The blending model was built by utilizing Finite Impulse Response Neural Network (FIR-NN) and variable selection is perform using Priciple Component Analys is (PCA) and Partial Least Square (PLS). The result of optimization resulted a decreasing the production cost up to 342 IDR/kWh.
Urban strategies to promote resilient cities The case of enhancing Historic C...inventionjournals
This research tackles disaster prevention problems in dense urban areas, concentrating on the urban fire challenge in Historic Cairo district, Egypt, through disaster risk management approach. The study area suffers from the strike of several urban fire outbreaks, that resulted in disfiguring historic monuments and destroying unregulated traditional markets. Therefore, the study investigates the significance of hazard management and how can urban strategies improve the city resilient through reducing the impact of natural and man-made threats. The main findings of the research are the determination of the vulnerability factors in Historic Cairo district, either regarding management deficiency or issues related to the existing urban form. It is found that the absence of the mitigation and preparedness phases is the main problem in the risk management cycle in the case study. Additionally, the coping initiatives adopted by local authorities to address risks are random and insufficient. The study concludes with recommendations which invoke incorporating hazard management stages (pre disaster, during disaster and post disaster) into the process of evolving development planning. Finally, solutions are offered to mitigate, prepare, respond and recover from fire disasters in the case study. The solutions include urban policies, land-use planning, urban design outlines, safety regulation and public awareness and training.
An image sensor or imaging sensor is a device that converts an optical image to an electric signal. It is used mostly in digital cameras and other imaging devices. This paper presents a high speed simulation methodology to reduce the long simulation time problem of traditional CMOS image sensor. A method based on spice model in cadence design platform is proposed to reduce the simulation time. This results simulation time reduced from 16ms to 0.225microsecond.
This document discusses wavelength assignment algorithms in WDM optical networks. It compares the random wavelength assignment algorithm to the first-fit algorithm in terms of blocking probability. Blocking probability is lower with the first-fit algorithm compared to the random algorithm. The document also examines the impact of wavelength conversion capabilities (no conversion, partial conversion, and full conversion) on blocking probability. Blocking probability is lowest when full wavelength conversion is possible. The first-fit algorithm performs better than random assignment even without wavelength conversion capabilities.
DWDM is a fiber optic transmission technique that uses different wavelengths of light to transmit multiple data signals simultaneously over the same fiber. This allows network capacity to be dramatically increased to meet rapidly growing bandwidth demands. DWDM provides a flexible solution to fiber exhaust and allows different data formats like IP, ATM, and SONET to be transported over a single optical network. By assigning each signal a unique wavelength, DWDM can multiply the capacity of existing fiber infrastructure.
Enhancing the Data Transmission Capability on Optical Fiber Communication Lin...IOSRJECE
This document discusses methods for enhancing data transmission capability on optical fiber communication links by overcoming dispersion. Dispersion limits the performance of optical communication systems in terms of high-speed data transmission. The document examines different dispersion compensation techniques including chirped fiber gratings, dispersion compensation fibers, and self-phase modulation resulting from Kerr nonlinearity. Chirped fiber gratings introduce varying delays to different wavelengths to counteract pulse broadening from group velocity dispersion. Dispersion compensation fibers with high negative dispersion are used to offset the positive dispersion of standard fibers. Self-phase modulation from optical fiber nonlinearity can also balance the negative frequency chirp from anomalous dispersion, allowing solitons to propagate without broadening. These dispersion compensation methods aim to
1) The document discusses channel estimation techniques for 4G wireless networks using OFDM modulation.
2) Channel estimation is important for coherent detection and diversity techniques in wireless systems, which have time-varying channels. Accurate channel estimation allows techniques like maximal ratio combining.
3) OFDM divides the channel into multiple sub-carriers to combat multipath fading and make channel equalization easier compared to single carrier systems. Channel estimation is needed to characterize the time-varying frequency response of the wireless channel.
This document provides an overview of basic WDM optical networks. It describes WDM as a multiplexing technique that allows multiple wavelengths to be transmitted over the same fiber. There are two main architectures: broadcast and select, which uses a simple star topology, and wavelength routed, which establishes light paths between nodes using the same wavelength. The document outlines the key components and working principles of each architecture, including their advantages and disadvantages. Wavelength routed networks allow for wavelength reuse but require efficient wavelength assignment to avoid bandwidth loss.
RECONFIGURABLE OPTICAL ADD AND DROP MULTIPLEXERS A REVIEWecijjournal
Optical multiplexing is the key function of a WDM network and reliable method for data transport networks. WDM networks configured as rings/mesh along with Optical Add-Drop Multiplexers supports added flexibility, simplicity and augment the spectral efficiency. Further enhancement achieved with Reconfigurable OADM architectures, growing briskly along with automatic network management, let the transport network to acclimatize with dynamically varying environment and flexibly respond to the transport network changes. It permits single or many wavelengths to be added and/or dropped from a
transport fiber without optical-to-electrical-to-optical domain translation. Presently ROADM technology
has revolutionized optical networking and an inseparable part of modern optical communication offering huge bandwidth for data transport at minimum expense. In this view the article presents comprehensive study for numerous generations of ROADM and their architecture and persistent development
IRJET- Design & Performance Analysis of MIMO-FSO Communication System Bas...IRJET Journal
The document summarizes a study on a MIMO-FSO (multiple-input multiple-output free-space optical) communication system using spectrum slicing wavelength division multiplexing (SS-WDM) technique. The system was tested with 4 channels at data rates up to 10Gb/s. The wavelengths ranged from 1550.11nm to 1552.52nm. The results showed the SS-WDM MIMO-FSO system was able to transmit data over 2.5 kilometers with a bit error rate of less than 10-9, even with atmospheric attenuation. The SS-WDM approach improved system performance under different weather conditions compared to non-sliced systems.
Performance Analysis of OFDM in Combating Multipath FadingIOSR Journals
Mobile Communication system has been on high rampage for high data transmission over wireless
medium with various challenges caused by the transmission Channel. OFDM is been discovered in recent years
to deal with this problems because of its ability to elegantly cope with multipath interference. This paper
investigates the performance of different modulation schemes using M-ary Phase Shift Keying (M-PSK) and Mary
Quadrature Amplitude Modulation (M-QAM) in information transmission with OFDM technique over Ideal
channel AWGN and worst channel Rayleigh Fading channel in terms of Bits Error Rate (BER). Analysis was
made for different types of modulation schemes BPSK, QPSK, 4-QAM and 16-QAM gray coded bit mapping.
Also, a feasibility of OFDM been used to combat multipath fading was analyzed with comparison between a
single carrier technique and OFDM multicarrier technique. Variation between SNR results with respect to BER
is plotted to show the trade off differences between the modulation schemes with the result showing that OFDM
allows data transmission with minimal error over fading channel than a Single Carrier
This document provides an overview of Dense Wavelength Division Multiplexing (DWDM) technology. It discusses key topics such as optical transmission, DWDM components like multiplexers/demultiplexers and amplifiers, DWDM networks and topologies, and transmission quality parameters. The presentation contains 32 slides and is intended to briefly explain DWDM as a means of achieving effective fiber-optic transmission and increasing bandwidth.
The document discusses recent advances in optical network technology, including components such as wavelength division multiplexing (WDM) systems, optical cross-connects, and optical switching technologies like MEMS. It outlines commercially available high-capacity optical systems providing terabits per second of capacity, as well as experimental WDM systems demonstrating multi-terabit capacities over long transmission distances. Emerging next generation optical networks are envisioned to be transparent, dynamic, and have switching at the wavelength level.
An important role performed by Zero Padding (ZP) in multi-band OFDM (MB-OFDM) System.
This role show for low-complexity in résistance against multipath interference by reducing
inter-carrier interference (ICI) and eliminating the inter-symbol interference (ISI) Also, zeropadded
suffix can be used to eliminate ripples in the power spectral density in order to conform
to FCC requirements.
At the receiver of MB-OFDM system needs to use of a technique called as overlap-and-add
(OLA). Which maintain the circular convolution property and take the multipath energy of the
channel.
In this paper, we proposed a method of performing overlap-and-add length for zero padded
suffixes. Then, we studied the effect of this method, dynamic optimization of overlap-and-add
(OLA) equalization, on the performance of MBOFDM system on Bit Error Rate (BER) with
AWGN channel and Saleh-Valenzuela (S-V) Multipath channel Model.
In the dynamic optimization OLA, the Length of ZP depends on length of channel impulse
response (CIR). These measures, based on SNR, insert the ZP according to the measurement.
Dynamic optimization of length of ZP improves the Performance of MBOFDM system. In fact
we developed a technique to select the length of ZP as function of SNR and CIR
estimate(repetition). In our simulation this technique improve to 3 dB at BER=10-2 with a
multipath channels CM4.
Dense wavelength division multiplexing (DWDM) is a fiber optic transmission technique that employs light wavelengths to transmit data parallel-by-bit or serial-by-character. It allows for increased fiber capacity and scalability. DWDM evolved from earlier WDM techniques and can transmit 64 or more channels through a single fiber using spacing between 25-50 GHz. Ongoing research focuses on reducing dispersion and developing tunable lasers. DWDM provides a robust, simple, and cost-effective solution for growing bandwidth demands.
International Journal of Computational Engineering Research(IJCER) ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
About Quality of Optical Channels in Wavelength Division Multiplexing Systems...TELKOMNIKA JOURNAL
Researches and the analysis of factors of the systems influencing quality with division according to radiation wavelength are given in article. Especially the communication quality in systems with wave division of channels is influenced by hindrances from Four Wave Mixing. In this regard the technique of definition of number of products of nonlinear effect of Four Wave Mixing getting to ranges of working channels, results of calculation of combinational products for the different number of channels in systems with division according to radiation wavelength is given. Power of a hindrance of Four Wave Mixing in systems with wave division of channels is calculated. Methods of reduction of influences of these nonlinear effects are considered. Conclusions and recommendations on ensuring quality of optical channels are provided in systems with wave division.
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Alcatel-Lucent has commercially launched next generation 100G coherent technology in their 1830 Photonic Service Switch (PSS). This provides the highest density of 100G with up to 5x100G per shelf or 15x100G per bay. It offers best-in-class performance through integrated ultra fast electro-optics and Bell Labs innovation. Softbank Telecom has selected this solution to upgrade their Japanese backbone network to support increasing bandwidth demands.
This document discusses dispersion compensation techniques for optical code division multiple access (OCDMA) systems using dispersion compensation fiber (DCF) and fiber gratings. It compares the performance of an 8-user OCDMA system using DCF versus fiber gratings. The results show that DCF more effectively compensates for dispersion, as evidenced by a lower bit error rate and higher Q factor, making it a better dispersion compensation method for OCDMA systems compared to fiber gratings.
Application WDM(wavelength division multiplexing) For COMPSEPatel Ankit
This document discusses the application of wavelength division multiplexing (WDM) in three contexts:
1) Fibre optics, where WDM is used to transmit multiple high-speed digital data streams over a single optical fibre by assigning each stream a dedicated wavelength of light.
2) Aircraft applications, where WDM can enable future aircraft networks that have high capacity, flexibility, security and low cost.
3) RF avionics, where WDM transmission of RF signals over optical fibre has advantages over coaxial cable by offering higher bandwidth and immunity to electromagnetic interference.
Isolation and characterisation of Nitrogen Fixing Bacteria ( Azotobacter Sp.)...inventionjournals
Different strains of Azotobactersp were isolated and charaterised morphologically, folowing their resistance activities against antibiotic and Nacl from Dooars and Darjeeling region of North Bengal.The soil sample studied were DS-1, DS-2 and DJ-1. DS-1 have 50 isolates, DS-2 have 45 isolates and DJ-1 have 50 isolates. Among morphlogical parameter colony colour, shape and size has been considered for this study. Most of the colony are white many shows colour, circular, colony diameter ranges from 1-4.5 cm . Four strains namely DS-1-18, DS-1-25,DS-2-10,DJ-1-45 shows resistance against anibiotic 35mg/l). Nacl tolerance activities of seveteen promising clone has studied, among them three strains namely DS-1-16, DS-1-17and DS- 2-18 shows salt tolerance of upto 4.5%.Nitrogen fixing capacityof five strains has been carried out for highest antibiotic resistance starins, among them DS-2-10 shows maximum N2 content (0.006 %)
Performance Evaluation of Thermoelectric Materials: A Case Study of Orthorhom...inventionjournals
Designers often face the predicament of non-standardized and poor performing materials for thermoelectric module manufacturing. Other than analytical means, the only method to evaluate the performance of thermoelectric materials would be through experimental means. This work studies the experimental approach employed in performance investigation of thermoelectric materials using Orthorhombic SnSe crystals as a case study. The result obtained reveals the high thermoelectric conversion efficiency of orthorhombic crystals, and that they can operate as both low and high temperature thermoelectric material.
Optimization of Coal Blending to Reduce Production Cost and Increase Energy E...inventionjournals
The productivity level of the electricity production is an important indicator in the power plant efficiency. A chase study in this research was choosen at coal power plant PT PJB UP Paiton which is the productivity level of the generated electricity decreases until below the production target level. It due to several factors such as quality of coal and plant design. Depletion of coal heating value (low rank coal) reduce total amount of enerated heat in boiler and finally increase unburned carbon, plant inefficiency, as well as the high production cost. On the other hand, utilizing the high rank coal cause more expensive price. Therefore, the optimiation of coal blending to obtain more plant efficiency and lower production cost is required. This research focus on optimization of low and high rank coal blending that can decrease the production cost and increase plat efficiency. The blending model was built by utilizing Finite Impulse Response Neural Network (FIR-NN) and variable selection is perform using Priciple Component Analys is (PCA) and Partial Least Square (PLS). The result of optimization resulted a decreasing the production cost up to 342 IDR/kWh.
Urban strategies to promote resilient cities The case of enhancing Historic C...inventionjournals
This research tackles disaster prevention problems in dense urban areas, concentrating on the urban fire challenge in Historic Cairo district, Egypt, through disaster risk management approach. The study area suffers from the strike of several urban fire outbreaks, that resulted in disfiguring historic monuments and destroying unregulated traditional markets. Therefore, the study investigates the significance of hazard management and how can urban strategies improve the city resilient through reducing the impact of natural and man-made threats. The main findings of the research are the determination of the vulnerability factors in Historic Cairo district, either regarding management deficiency or issues related to the existing urban form. It is found that the absence of the mitigation and preparedness phases is the main problem in the risk management cycle in the case study. Additionally, the coping initiatives adopted by local authorities to address risks are random and insufficient. The study concludes with recommendations which invoke incorporating hazard management stages (pre disaster, during disaster and post disaster) into the process of evolving development planning. Finally, solutions are offered to mitigate, prepare, respond and recover from fire disasters in the case study. The solutions include urban policies, land-use planning, urban design outlines, safety regulation and public awareness and training.
An image sensor or imaging sensor is a device that converts an optical image to an electric signal. It is used mostly in digital cameras and other imaging devices. This paper presents a high speed simulation methodology to reduce the long simulation time problem of traditional CMOS image sensor. A method based on spice model in cadence design platform is proposed to reduce the simulation time. This results simulation time reduced from 16ms to 0.225microsecond.
The Economic Comparison Between Dry Natural Gas And Nitrogen Gas For Strippin...inventionjournals
Natural gas isa substantial energy source among other sources of fossil fuels. It is usually produced saturated with water vapor under production conditions. The natural gas dehydration is very paramount in the gas industry to stripthe water vapor existing in the gas production, at low-temperature conditions that may plug the system because of hydrate formation in pipelines. Totake off water vapor from natural gas flow usestriethylene glycol (TEG) in the gas dehydration process. In the glycol method, the wet gas is contactwith leanglycolinan absorber to dehydrate naturalgas and the rich glycol will be recovered and used again. This paper deals with stripping gas in the regenerator of glycol dehydration package with part of dry natural gas instead of nitrogen for stripping water vapor from triethylene glycol and studying the economic comparison between both of them by using modeling and simulation with HYSYS program. The two methods were investigated and evaluated to choose the optimal one with respect to the capital and utility costs, provided that keeping the same specifications and quantity of the glycol purity.In addition, the wet gas from the stripping process can be used to operate texsteam pumps and compressors or recycle with wet gas feed. The model has been built according to the actual process flow diagram. Finally, the results of this model could be considered as a basis on which a new heat and material balance will be developed for the plant.
The reconstruction of the metabolic network of an organism based on its genome sequence is a key challenge in systems biology. The aim of the work described here is to develop a new algorithm to predict pathway classes and individual pathways for a previously unknown query molecule. The main idea is to use a dense graph, where the compounds are represented as vertices and the enzymes are represented as edges, the weights are assigned to the edges according to the previous known pathways. The shortest path algorithm is applied for each missing enzyme in a pathway. A pathway is considered belong to an organism if the total cost between the initial and final compound is higher than a threshold. Validation experiments show that the suggested algorithm is capable to classify more than 90% of pathways correctly
Mapping the Wind Power Density and Weibull Parameters for Some Libyan Citiesinventionjournals
In order to introduce a well-informed decision regarding positioning of wind farm projects, prior intensive data collection, processing, and analysis are required. In this paper, wind data of twenty-five Libyan cities has been collected, processed, and analyzed to determine Weibull distribution parameters and the wind energy density for each of the twenty-five cities. The study is based on a recorded historical data from NASA of air temperature, barometric pressure, and wind speed for ten years along the period from January 1 st, 2005 to December 31st, 2014. The data used are the daily average values for each of the three parameters. Three methods have been used to estimate Weibull parameters namely: 1) the power density method, 2) the maximum likelihood method, and 3) the moment method. The goodness-of-fit for each method is, then, compared using the mean absolute error and the root mean square error methods. Lack of information regarding wind energy surveys for this particular region was one of the key factors in conducting such a comprehensive analysis.
The sun is the source of solar energy and the solar energy is pollution free and available in ample amount which can be used for heating, electricity generation and coking purpose.The position of sun constantly varies so its intensity also varies which affect the heat quantity incident upon the system. The aim of present work is overcome this difficultly using wax type phase change material which behaves like heat storage medium as position of sun changes. This phase change material based solar water heater is fabricated and thermal performance evaluation can be carried out using K type thermocouple.
Effective Project Preparation Process: A Key Factor to a Successful PPP Infra...inventionjournals
Management of PPP project preparation process according to WEF (2013) is quite complex because it involves large team and multiple stakeholders such as ministries, regulatory organs and regulations, engineering firms, banks as well as multiple interfaces between different project functional feasibility studies. It is therefore very important at this stage to put together capable and experienced cross-functional project team supported by committed political and project leadership in order to achieve a sustainable PPP project preparation process. The main feature of a PPP project preparation process includes; project planning, project coordination and project monitoring. This process according to Adamuet al. (2015) can be cost intensive, therefore the public sector needs to ensure sufficient upfront funding of the entire process.This study is aimed at assessing the effectiveness of road project preparation process in the development of road infrastructure under PPP concession. In order to achieve this aim, the study examined the concept of PPP models for infrastructure development and project preparation process in a PPP framework. Data collection was through administration of well-structured questionnaire on the target population. Data collected were analysed using both descriptive and inferential statistic analytical techniques.The study revealed that there is urgent need to review the current Nigeria National Policy on PPP, institutional structure and individual capacity building in the area of PPP project preparation in order to encourage more private sector participation in the drive for provision and development of road infrastructure facility.
On Triplet of Positive Integers Such That the Sum of Any Two of Them is a Per...inventionjournals
In this article we discussed determination of distinct positive integers a, b, c such that a + b, a + c, b + c are perfect squares. We can determine infinitely many such triplets. There are such four tuples and from them eliminating any one number we obtain triplets with the specific property. We can also obtain infinitely many such triplets from a single triplet.
Antiemetic Prophylaxis in Major Gynaecological Surgery With Intravenous Grani...inventionjournals
In a randomized double-blind study, researchers compared the efficacy of granisetron versus metoclopramide for preventing postoperative nausea and vomiting (PONV) in 50 female patients undergoing major gynecological surgery. Patients received either granisetron 40mcg/kg or metoclopramide 0.15mg/kg before surgery. Incidence of PONV was assessed over 24 hours. While both drugs effectively prevented PONV in the first 4 hours, granisetron was more effective over the next 20 hours, with a 12% incidence of PONV versus 48% for metoclopramide. Nausea scores were also significantly lower in the granisetron group
The Odd Generalized Exponential Log Logistic Distributioninventionjournals
We propose a new lifetime model, called the odd generalized exponential log logistic distribution (OGELLD).We obtain some of its mathematical properties. Some structural properties of the new distribution are studied. The maximum likelihood method is used for estimating the model parameters and the Fisher’s information matrix is derived. We illustrate the usefulness of the proposed model by applications to real lifetime data.
We presented a Finsler space 퐹푛 whose Cartan's fourth curvature tensor 퐾푗푘 ℎ 푖 satisfies 퐾푗푘 ℎ|ℓ |푚 푖 = 휆ℓ 퐾푗푘 ℎ|푚 푖 + 푏ℓ푚 퐾푗푘 ℎ 푖 , 퐾푗푘 ℎ 푖 ≠ 0, where 휆ℓ and 푏ℓ푚 are non-zero covariant vector field and covariant tensor field of second order, respectively. such space is called as 퐾 ℎ –generalized birecurrent space and denoted briefly by 퐾 ℎ – 퐺퐵푅– 퐹푛 . In the present paper we shall obtain some generalized birecurrent tensor in an 퐾 ℎ − 퐺퐵푅 − 퐹푛 .
Free-scale Magnification for Single-Pixel-Width Alphabetic Typeface Charactersinventionjournals
This document presents a novel approach for magnifying single-pixel-width alphabetic typeface characters. It first removes useless serif patterns from the character. It then applies an intuitive stroke transcribing algorithm to describe the character. Each stroke, represented by cubic B-spline functions, is scaled using wavelet transform with arbitrary size. Experimental results on computer fonts show the proposed algorithm performs magnification well while maintaining character shape and structure without additional distortion.
“Desquamative Gingivitis Treated By An Antioxidant Therapy- A Case Report”inventionjournals
This case report describes the successful treatment of desquamative gingivitis in a 52-year-old female patient using systemic antioxidant therapy. Desquamative gingivitis causes red, eroded patches on the gums. While topical steroids provided no improvement, taking an herbal antioxidant capsule containing extracts of various plants twice daily for two months resolved the lesions with no recurrence. Antioxidants can reduce oxidative damage and inflammation, providing an alternative to steroids for treating desquamative gingivitis.
Some Properties of M-projective Curvature Tensor on Generalized Sasakian-Spac...inventionjournals
The document summarizes research on properties of the M-projective curvature tensor on generalized Sasakian-space-forms. Key points:
- It studies whether generalized Sasakian-space-forms are M-projectively semisymmetric (curvature tensor satisfies a certain condition) or M-projectively pseudosymmetric.
- It is shown that an M-projectively semisymmetric generalized Sasakian-space-form is either M-projectively flat or satisfies a specific condition on the structure functions.
- No conclusion is drawn about M-projectively pseudosymmetric generalized Sasakian-space-forms. The research aims to classify these manifolds based on properties of the M
ASSESSMENT OF NANOPARTICULATED RESVERATROL AND LOSARTAN IN THE PROPHYLAXIS OF...inventionjournals
The study demonstrated that eight weeks after bilateral ovariectomy in female white Wistar rats, develops endothelial dysfunction of bone microvasculature and deterioration of regional blood flow in the bone, leading to the emergence of generalized osteoporosis. Nanoparticulated forms of Losartan and Nanoparticulated forms of Resveratrol, possessing endothelial protective action, effectively prevent the reduction of regional microcirculation in bone tissue, keeping it at the level of intact rats. It is allowed to maintain an adequate level of bone remodeling processes, which manifested by slowing the thinning of bone trabeculae.
Kinetics and Thermodynamics of Mandelic Acid Oxidation By Tripropylammonium H...inventionjournals
Two new Versatile reagent Tripropylammonium Fluorochromate(TriPAFC) and Tripropylammonium Chlorochromate(TriPACC) has been employed for the oxidation of Mandelic acid. Rate of the réaction is catalysed by surfactant Sodium LaurylEther Sulphate(SLES). The Oxidation has been studied spectrophotometrically at room température in perchloric acid medium. Rate of TriPAFC and TriPACC oxidation of Mandelic acid has been followed under pseudo-first order condition. Rate constants were calculated by the integrated rate equation. The graph of logk versus time was linear and the slope is near to unity, rate constant calculated from graph also agreed with experimental value shows the first order rate dépendance on Mandelic acid. Product formed in this oxidation of Mandelic acid was analysed, polymerization test were carried to confirm that the reaction follows ionic mechanism and stoichiometric data has been accounted.Temperature of the substrate is varried and from the rate constant value, Thermodynamic parameters like Activation energy, Enthalpy change, Entropy change and change in Gibb’s free energy is calculated using Arrhenius and Eyrings plot. All the kinetic runs were repeated and the rate constants were reproducible within ±2% range.
Cytogenetic, Hematological and Enzymes Levels Parameters in the Biomonitoring...inventionjournals
This study assessed the genotoxic effects of pesticide exposure on 61 agricultural workers in Piauí, Brazil. Workers exposed to pesticides had significantly higher numbers of micronuclei in buccal mucosa cells compared to unexposed controls, indicating cytogenetic damage. No significant increases were found for hematological or enzyme levels. Longer exposure time (10 years vs 1 year) correlated with higher micronuclei frequency, and smoking/alcohol consumption among long-term exposed workers was also associated with more micronuclei. The results suggest occupational pesticide exposure induces genetic damage detectable via the micronucleus test.
Cytogenetic, Hematological and Enzymes Levels Parameters in the Biomonitoring...
Similar to The Effect of PMD (Polarization Mode Dispersion) the Fibers of New and Old In Different Distance in Numerical Systems with Optical Fiber WDM
Mitigation of non-linear four-wave mixing phenomenon in a fully optical commu...TELKOMNIKA JOURNAL
This paper aims to point out the nonlinear phenomenon occurring in coarse/dense wavelength division multiplex (C/D-WDM) systems. This phenomenon has to betaken into account during the design of the optical network itself, as wavelengthsin the optical fiber are constantly densified. The paper points out the emergence of the non-linear four-wave mixing (FWM) phenomenonand how it relates to the dispersion in the optical fiber together with the transmit power. The output of the paper is a proposed design of the system that points to the improvement of the bit error rate (BER) with a suitable choice of dispersion and suitable transmission power.
Integrated DWDM and MIMO-OFDM System for 4G High Capacity Mobile Communicatio...CSCJournals
This document describes a simulation of an integrated 64-channel dense wavelength division multiplexing (DWDM) system with multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) technology for high-capacity 4G mobile communication. The DWDM transmitter is designed to transmit baseband non-return-to-zero signals over fiber at 10 Gbps per channel for a total of 640 Gbps. After transmission over fiber with dispersion compensation, the signals are input to the MIMO-OFDM system. Space-time block coding is used to provide diversity in the MIMO-OFDM system. The performance is analyzed in terms of bit error rate with signal-to-noise ratio, achieving a desirable B
Empirical analysis of polarization division multiplexing-dense wavelength di...IJECEIAES
This paper exemplifies dense wavelength division multiplexing combined with polarization division multiplexing with C-band frequency range-based single-mode fiber. In the proposed link, 32 independent channels with 16 individual wavelengths are multiplexed with two different angles of polarization. Each carrying 130 Gbps dual-polarization data with 200 GHz channel spacing claiming a net transmission rate of 4.16 Tbits/s with spectral efficiency of 69% with 20% side-mode-suppression-ratio (SMSR) and optical signal to noise ratio (OSNR) 40.7. The performance of the proposed techniques has been analyzed using optimized system parameters securing a minimum bit error rate (BER) 10-9 at a transmission distance up to 50 km.
1) The document discusses reducing the effect of dispersion resulting from wavelength division multiplexing (WDM) in optical networks. Dispersion occurs when light pulses spread out as they travel through fiber optic cables, which degrades signal quality over long distances.
2) WDM is used to increase network capacity but also introduces longer fiber lengths, exacerbating dispersion issues. Different types of dispersion are discussed, including chromatic dispersion which causes slower wavelengths to interfere with faster wavelengths from adjacent pulses.
3) Chromatic dispersion is modeled and compensated for using Gaussian minimum-shift keying modulation and linear filters, which can be applied at the transmitter or receiver to counteract the spreading effect of the fiber on light pulses.
This document provides an overview of dense wavelength division multiplexing (DWDM) technology. It discusses the history and components of a DWDM system, including transponders, multiplexers, fiber, amplifiers, and demultiplexers. It covers limiting factors such as linear and nonlinear effects that must be considered for DWDM systems. The document also discusses measurements and tests needed for DWDM system installation, optimization, and acceptance.
Design and Performance Study of MMDWDM Systemselelijjournal
The rising need for bandwidth created innumerable efforts from academic and industry group towards development of most efficient optical communication networks. In order to compete it numerous investigators have designed their own novel schemes. In this view the paper presents multiple modulation dense wavelength division multiplexed transmission designed links each with a total capacity of 640Gbps and with channel to channel to spacing of 100Ghz, employing multiple modulation schemes such as non return to zero rectangular, non return to zero raised cosine, return to zero rectangular, non return to zero raised cosine, return to zero soliton, return to zero Super Gaussian. The optical transmission performance characteristics like bit error rate, Q parameter at the output have been investigated by simulating different systems for a fixed transmission length of 260kilometers. Results show that transmission performance of DWDM system with non return to zero raised cosine scheme has been better with quality factor ranging from 16 to 23dB and bit error rate ranging from 10-11 to 10-40 for detected channels at selected transmission reach (260KM) and other schemes with good performance were RZ Super Guassian DWDM and RZ Soliton DWDM systems for the same transmission reach. The transmission parameter jitter have been also investigated for each system which depict that jitter effect is more severe for return to zero systems as compared to non return to zero DWDM systems. From the performance analysis for different optical links involving different modulation schemes it can be articulated that novel modulation scheme generally improves the transmission performance and must for modern optical communication systems operating at high bit rate and longer reach.
In this work, high-speed transmission over the long-haul optical channel using orthogonal frequency division multiplexing (OFDM) was investigated. Furthermore, we recommend mixing polarization division multiplexing (PDM) with coherent OFDM (CO-OFDM) and quadrature amplitude modulation (16-QAM) to improve spectral efficiency (SE) while transmitting over a wavelength division multiplexing (WDM) system.
An 800 Gb/s WDM PDM-CO-OFDM-16QAM transmission system with various channel spacing of 100 GHz, 50 GHz, and 25 GHz is examined utilizing the OptiSystem (2021) version 18.0 software package over ten spans of 60 km standard single-mode fiber (SSMF). Different channel spacing WDM systems have been compared in terms of performance and SE. The results reveal that the WDM system with 100 GHz channel spacing has a longer transmission range and needs minimal optical signal to noise ratio (OSNR) at the reception. The 25 GHz channel spacing WDM system exceeds the others in terms of SE. Further, the effect of ultra-low loss and large effective area fiber in lowering span loss and nonlinear effects for
25 GHz channel spacing WDM system is investigated. The findings show that the system performance with the new fiber outperforms the SSMF.
The acceptable bit error rate (BER) for this study is 0.033 (20% concatenated forward error correction (FEC) threshold).
This document provides an overview of wavelength division multiplexing (WDM) technology. It begins with introducing optical fibers and their components. It then discusses multiplexing techniques like time-division multiplexing (TDM) and frequency-division multiplexing (FDM). The document focuses on WDM, defining it as a technology that multiplexes multiple optical signals on a single fiber using different laser light wavelengths. It describes dense WDM (DWDM) and coarse WDM (CWDM), and compares their wavelength spacing and applications. The document also outlines optical amplifiers like erbium-doped fiber amplifiers and their uses. In conclusion, it states that WDM enables high-speed, high-capacity data transmission and
Dense wavelength division multiplexing (DWDM): A Review Kamal Pradhan
it is clear that as we approach the 21st century the remarkable revolution in information services has
permeated our society. This rapid growth of information technology has led to new services hungry for transmission
capacity. Communication, which in the past was confined to narrowband voice signals, now demands a high quality
visual, audio, and data context for services such as Voice over-Internet protocol (VoIP), video streaming,
broadcasting of TV programmes, high-speed file sharing, E-commerce and E-Governance need a transmission
medium with very high bandwidth capabilities for handling vast amounts of information. The telecommunications
industry, however, is struggling to keep pace with these changes. Earlier predictions were made that current fiber
capacities would be adequate for our needs into the next century but they have been proven wrong but these fiber-
optics, with its comparatively infinite bandwidth and by employing the latest multiplexing technique, i.e. Dense
Wavelength Division Multiplexing (DWDM) has proven to be the solution.
RECONFIGURABLE OPTICAL ADD AND DROP MULTIPLEXERS A REVIEW ecij
Optical multiplexing is the key function of a WDM network and reliable method for data transport networks. WDM networks configured as rings/mesh along with Optical Add-Drop Multiplexers supports added flexibility, simplicity and augment the spectral efficiency. Further enhancement achieved with
Reconfigurable OADM architectures, growing briskly along with automatic network management, let the transport network to acclimatize with dynamically varying environment and flexibly respond to the transport network changes. It permits single or many wavelengths to be added and/or dropped from a
transport fiber without optical-to-electrical-to-optical domain translation. Presently ROADM technology has revolutionized optical networking and an inseparable part of modern optical communication offering huge bandwidth for data transport at minimum expense. In this view the article presents comprehensive study for numerous generations of ROADM and their architecture and persistent development.
Optical space division multiplexing uses multiple cores or modes in optical fibers to increase transmission capacity. A history of the technology was provided, noting the progression from single mode fibers to coherent detection and polarization multiplexing. Limits with single mode fibers were discussed, along with ways that multi-core and multi-mode fibers can overcome capacity constraints through spatial multiplexing across fiber cores and modes. Recent demonstrations showed record capacities of 57.6 Tb/s over multi-mode fiber and 24 Tb/s over hollow-core fiber. Integration challenges with spatial division multiplexing were also outlined.
Analysis of System Capacity and Spectral Efficiency of Fixed-Grid NetworkIJCNCJournal
In this article, the performance of a fixed grid network is examined for various modulation formats to estimate the system's capacity and spectral efficiency. The optical In-phase Quadrature Modulator (IQM) structure is used to build a fixed grid network modulation, and the homodyne detection approach is used for the receiver. Data multiplexing is accomplished using the Polarization Division Multiplexed (PDM) technology. 100 Gbps, 150 Gbps, and 200 Gbps data rates are transmitted under these circumstances utilizing various modulation formats. Various pre-processing and signal recovery steps are explained by using modern digital signal processing systems. The achieved spectrum efficiencies for PM-QPSK, PM-8 QAM, and PM-16 QAM, respectively, were 2, 3, and 4 (bits/s)/Hz. Different modulation like PM-QPSK, PM-8-QAM, and PM-16-QAM each has system capacities of 8-9, 12-13.5, and 16-18 Tbps and it reaches transmission distances of 3000, 1300, and 700 kilometers with acceptable Bit Error Rate (BER≤ 2× 10-3) respectively. Peak optical power for received signal detection and full width at half maximum is noted for the different modulations under a fixed grind network.
RZ based dispersion compensation technique in dwdm system for broadband spectrumRamesh Patriotic
This document summarizes a study on using return-to-zero (RZ) pulse modulation and dispersion compensation techniques in dense wavelength division multiplexing (DWDM) systems. The study designs an 8-channel DWDM system using RZ pulse modulation at 2.5 Gbps over 100km of single-mode fiber. Dispersion compensation fiber is placed before the transmission fiber to reduce dispersion effects. Simulation results show that the RZ modulation technique offers improved eye diagrams, higher Q-factors, lower bit error rates, and broader transmitted spectra compared to non-return-to-zero modulation, indicating better performance for long-haul optical communication networks.
Iisrt 1-rz based dispersion compensation technique in dwdm system for broadba...IISRTJournals
This document summarizes a study on using return-to-zero (RZ) pulse generation and dispersion compensation techniques in dense wavelength division multiplexing (DWDM) systems to achieve broadband transmission over long distances. The study used simulation software to model an 8-channel DWDM system with and without dispersion compensation fibers. Results showed that using RZ pulses and dispersion compensation fibers improved key performance metrics like Q-factor and minimum bit error rate compared to non-return-to-zero pulses over a 100km single mode fiber link. Graphs and eye diagrams demonstrated lower jitter and better signal quality when using the RZ and dispersion compensation technique.
RZ based dispersion compensation technique in dwdm system for broadband spectrumIISRT
This document summarizes a study on using return-to-zero (RZ) pulse generation and dispersion compensation techniques in dense wavelength division multiplexing (DWDM) systems to achieve broadband transmission over long distances. The study used simulation software to model an 8-channel DWDM system with and without dispersion compensation fibers. Results showed that using RZ pulses and dispersion compensation fibers improved key performance metrics like Q-factor and minimum bit error rate compared to non-return-to-zero pulses without compensation. Analysis of eye diagrams and spectra also demonstrated lower distortion and broader transmission bandwidth when using the RZ and compensation technique.
Analysis of System Capacity and Spectral Efficiency of Fixed-Grid NetworkIJCNCJournal
The document analyzes the system capacity and spectral efficiency of a fixed-grid optical network using different modulation formats. It simulates a fixed-grid network using polarization division multiplexing and transmits 100-200 Gbps data rates using PM-QPSK, PM-8QAM, and PM-16QAM modulation. The achieved spectral efficiencies were 2, 3, and 4 bits/s/Hz respectively. The modulation formats provided system capacities of 8-9, 12-13.5, and 16-18 Tbps, reaching transmission distances of 3000, 1300, and 700 km with a bit error rate below 2x10-3. It examines the received optical power and bandwidth requirements for different modulations in a fixed grid
Comparison of PMD Compensation in WDM SystemsIOSR Journals
Abstract: The need for larger capacities in long haul optical digital transmission lead to greater channel density which can be achieved by wavelength division multiplexing and increasing the bit rate of each channel. As data rates increases, certain phenomena such as dispersion began to show up as obstacles. At higher bit rates beyond 2.5Gbps polarization mode dispersion (PMD) becomes a main factor in the degradation of the transmission characteristics. PMD occurs when slightly different planes of light inside a fiber travel at slightly different speeds and make it impossible to transmit data reliably at high speed in single mode fibers. PMD is caused due to optical birefringence in the fiber due to which the two modes within a single mode fiber travel with different group velocities and the random change of this birefringence along the fiber length results in random coupling between the modes. This effect of PMD results in broadening of transmitted pulses that limit the transmission capacity of the fiber. In high-speed optical communication systems working at data rates of 10Gbps and beyond, signal distortion caused by PMD is also a major limitation of the transmission distance. This paper intends to analyze the performance of PMD compensation by optical compensation technique and using DCF in a two channel WDM system. The analysis is done through eye diagrams from which the Q value and bit error rate can be determined by simulating with OptSim5.3, which includes the latest simulation algorithms to guarantee the highest possible accuracy and real world results. Keywords– Birefringence, Data rate, Deterministic Differential Group Delay (DDGD), Dispersion compensating fibers (DCFs) Polarization Mode Dispersion (PMD Principal State of Polarization (PSP), Q value.
Comparison of PMD Compensation in WDM SystemsIOSR Journals
The need for larger capacities in long haul optical digital transmission lead to greater channel
density which can be achieved by wavelength division multiplexing and increasing the bit rate of each channel.
As data rates increases, certain phenomena such as dispersion began to show up as obstacles. At higher bit
rates beyond 2.5Gbps polarization mode dispersion (PMD) becomes a main factor in the degradation of the
transmission characteristics. PMD occurs when slightly different planes of light inside a fiber travel at slightly
different speeds and make it impossible to transmit data reliably at high speed in single mode fibers. PMD is
caused due to optical birefringence in the fiber due to which the two modes within a single mode fiber travel
with different group velocities and the random change of this birefringence along the fiber length results in
random coupling between the modes. This effect of PMD results in broadening of transmitted pulses that limit
the transmission capacity of the fiber. In high-speed optical communication systems working at data rates of
10Gbps and beyond, signal distortion caused by PMD is also a major limitation of the transmission distance.
This paper intends to analyze the performance of PMD compensation by optical compensation technique and
using DCF in a two channel WDM system. The analysis is done through eye diagrams from which the Q value
and bit error rate can be determined by simulating with OptSim5.3, which includes the latest simulation
algorithms to guarantee the highest possible accuracy and real world results
This document describes a simulation of transmitting 20 channels of either 10 Gbps or 20 Gbps data over 80 km spans of conventional single mode fiber using wavelength division multiplexing in the L-band spectrum region. Both pre-compensation and post-compensation techniques for dispersion were considered. Post-compensation provided better performance with transmission distances of up to 720 km for a total throughput of 200 Gbps and 320 km for 400 Gbps, and lower bit error rates compared to pre-compensation. Non-linear effects and amplified spontaneous emission noise were also accounted for in the simulation.
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The Effect of PMD (Polarization Mode Dispersion) the Fibers of New and Old In Different Distance in Numerical Systems with Optical Fiber WDM
1. International Journal of Engineering Science Invention
ISSN (Online): 2319 – 6734, ISSN (Print): 2319 – 6726
www.ijesi.org ||Volume 5 Issue 8|| August 2016 || PP. 60-68
www.ijesi.org 60 | Page
The Effect of PMD (Polarization Mode Dispersion) the Fibers of
New and Old In Different Distance in Numerical Systems with
Optical Fiber WDM
Enis Çerri1
1
(Department of Information Technology / Aleksander Moisiu University of Durres, Albania)
Abstract : This is a study conducted in a laboratory at the university as a simulation to see the effect of new
fiber PMD for different distances. This is done to compare the performance of the digital system with optical
fiber WDM. In this simulation are not included remission, chromatic dispersion and nonlinear effects. In this
way all of the signal distortions caused only by different combinations of PDM. Polarization effects are very
important in communications systems with optical fiber. Optical fiber that is used mainly during the simulation
is a standard single mode fiber (SSMF).
Keywords: fiber-optic communication systems, standard single-mode fibers (SSMFs), polarization-mode
dispersion (PMD), polarization effects, WDM numeric system.
I. Introduction
Polarization efects in fiber-optic communication systems are usually related to fiber birefringence [1]. It is well
known that standard single-mode fibers (SSMFs) support two orthogonally-polarized modes [2]. These two
modes have almost the same propagation constant, and tend to travel at the same velocity [3]. When light
encountersany sort of perturbation or asymmetry within the fiber, it results very easy for optical energy to
transfer from one of these modes to the other. For suficiently long fibers, such perturbations or asymmetries lead
to random polarization rotation, polarization-mode coupling, and polarization-mode dispersion (PMD) [4-7].
The stochastic behavior of the polarization evolution in optical fibers is undesirable, since, most of the times, it
deteriorates the performance of the communication system [8].
Optical fiber communication is regarded as the best method for transmitting audio signals, video and data.
The advantage of maximum protection from electromagnetic interference, the wider band has conditioned the
extension of fiber systems in a wide range of applications very many fields including industry also.
Despite the greatly improved transmission system these systems maintain the basic techniques of analog signals
[9]. Now a new generation of products that fully implements digital signals to transmit analog information
provides the ability to raise the standard again, advancing optical fiber transmission with a completely new
level.
Based on the concept of modulation, multiplexing digital systems are important in the implementation of
systems with multichannel broadcasting. The most common methods for digital broadcasting in an optical
system is the direct correspondence information transmitted optical power level bit signal transmitted by
acquiring so-called intensity modulated (IM) [10]. The light emitted from the source entering the optical fiber
consists not only of a single beam of light but some such that hit the heart of the fiber with different angles.
In the fiber multi-mode beams have different paths of different lengths depending on the angle of the fall.
It is understood that the rays that fall with zero angle, parallel to the axis of the heart, depicting the same street
with the length of the fiber and rays that enter the maximum permitted angle describe the longest.
It is understood that fashion describing longest road pickup will have a time delay compared with axial beam.
This effect is caused as a result of various fashions spread of radiation known as modal dispersion or intermodal.
Measured by ns / km and increases with length [11].
1. The design of digital systems with optical fiber WDM
With the technique of wavelength division WDM allowed the aggregation of many basic channels (high
speed).No difference in concept between WDM and FDM techniques used in electrical communication
systems.In optical transmission environment can be defined spaces such frequency Δf. It came the task of
effective use of high-capacity fiber and it is entirely possible through optical multiplicity [12].Optical
multiplexing transmission comes as a need of more information in the same optical transmission medium.
Multiplexing term addresses a specific technical transmission processing stage that allows the use
simultaneously the same transmission medium (coaxial cable, radio wave, via satellite, optical fiber) of several
signals. In making have demultiplexing, the inverse operation of multiplicity, whereby the signal transmitted
recover [13].
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WDM systems can easily be implemented in each of the three technologies and architectures based
telecommunications networks. We can treat in this way point on a point system with high capacity 2.5 Gbps
where information flow can be viewed as independent flow SDH networks transmitted at the same carrier.WDM
represents the second generation of the evolution of optical fiber telecommunications [14]. The first
development occurred in the early 80's, when major phone companies bound the United States to other countries
with optical fiber thus creating a "network" of channels that enable the transmission of information and that can
carry greater capacity that simple conductors or microwave links [15].
Fig.1 Architecture of of digital systems with optical fiber WDM
WDM is another great progressive step that multiplies the capacity of fiber allowing transport not only one but
several different wavelengths, each able to carry different optical signals. So the whole spectrum uses optical
WDM attaching any color that constitutes a different channel data transmission. Components are used in WDM
passive components technique [16].
Typical features of the technology are:
1. Use low gang suppression of 1200-1600 nm.
2. Capacity to carry some Gbps WDM in the same channel.
3. The high number of channels multiplexed that can go to 100 channels.
4. Compliance WDM-TDM techniques in particular to reduce the number of holders wavelength.
Multiplexes and demultiplexes used in interfaces with transmitting and receiving stations.To ensure the
propagation distances of hundreds km optical amplifiers OA needed to use every 50-100 km. Compensation
systems are used as chromatic dispersion and dispersion compensation CDC to insert the fiber. WDM principle
appears simple and known by time. The reason why is not applied in prior periods have been appropriate optical
amplifiers. When the transmission systems used in optical fibers, the only way to ensure the long-distance
transmission was through signal regeneration opto-electronics [17].Recovery in these weaker broadcast
impulses transformed after the discovery of a photoelectric reconnaissance and amplified by a modulated laser
transmitter. The problem is that an inventor is not different wavelength from another.A network designers need
to optimize optical and electrical parameters to provide minor operations multiplicity DWDM network
[18].However topology using ring, mesh or point-to-point, system design must be considered divided into two
parts. The projection optical system and the electrical system or the projection of the upper classes of the system
[19].
Global optical network layer (WDM layer) appears as the physical layer which has the function of a series of
bits transmission with a high speed and a negligible loss. However, some transmission errors can be disastrous.
As long as the transmission distance and transmission speed are within the limits set (for example small nets) is
not required consideration of optical parameters [20].
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1.1 The polarization mode dispersion PMD
The polarization mode dispersion (PMD) is a feature of single-mode fiber where the spread pulsed modes
performed by the polarized that spread at different speeds. Optical fiber can be modeled through two polarized
orthogonal axes that can be called the initial conditions of polarization (PSP). The signal optical fiber spreads
divided into two components axes PSP. Any polarization axis (fast and slow) has spread at different speeds.
This is due to the different indices of refraction caused by inhomogeneous material.
Components of optical pulse propagating at different speeds lead to expansion in the making impulse for optical
receiver is insensitive to polarization of light downward. The amount of spread of impulses in time by
polarization axis is known as the differential group delay (DGD) and measured picosecond [ps]. The time it
takes an impulse to spread fiber is a group delay. DGD is an instant value that varies randomly along the length
of a fiber. PMD is defined as the amount of the linear average value of the group delay with respect to a
wavelength λ. PMD is measured in units of picoseconds [ps]. Fibre length greater than 2 km and average RMS
values are similar. The following equation shows the relationship between these two averages [21]:
𝑃𝑀𝐷𝑟𝑚𝑠 =
𝟑𝜋
𝟖
𝑃𝑀𝐷𝑚𝑒𝑠 (1)
PMDrms= 1.085 PMDmes (2)
Fig.2 Shows the two polarized orthogonal axes that causes PMD and the signal optical fiber spreads divided into
two components axes PSP which the amount of spread of impulses in time by polarization axis is known as the
differential group delay (DGD).
PMD becomes dominant at higher speeds over 5Gbps. PMD is caused by nonlinearity fiber. This asymmetry is
called birefrigrence where two polarization modes Ex and Ey are part of the phenomenon of overlapping. As a
result of this effect two ways does not mate with each other but the impulse is distributed in time. The main type
of PMD originates from dispersion wavelength of the signal depending on the signal spectrum. PMD is
expressed as a differential group delay DGD that difference becomes apparent as multiple spectral components
in a given fiber length. The polarization axes not grow together and sharing impulse transmission along the
fiber. The difference is proportional to the DGD.
So DGD used as a measure of PMD in a given system and is calculated by the equation. During the pulse spread
in the fiber optical random changes due to local fiber birefringence enable an impulsive part of the optical
power of a fashionable pair to another which is known as pairing mode (mode coupling). Experiments have
shown that fiber length greater than 2 km appear the greatest pairing mode and PMD is proportional to the
square root of the fiber length. PMD coefficient is measured with picosecond to the square root of a kilometer
[ps / √ km]. PMD coefficient is determined by the manufacturer of optical fiber and PMD represents
characteristic of a certain length. Often referred PMD coefficient PMD, which may cause confusion with these
two terms [22].
PMD = PMDc L (3)
where𝑃𝑀𝐷𝑐 expressing PMD coefficient.
Due to expansion impulse that travels along the optical fiber, PMD can cause interferanca intersimbol resulting
in errors in the signal transmitted. This effect is negligible and should be considered only in systems where the
transmission speed is equal to or greater than 10 Gbps. It should also be taken into consideration for analog
systems with fiber because of its contribution to the growth of signal distortion and reduce the OSNR [23].
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1.2 Causes of generation DGD
DGD due to birefringence of the fiber that comes as a result of pressure from the interior and exterior in fiber
and imperfect processes of production. In an ideal fiber of her heart geometry it is circular and therefore
symmetrical refraction indices along the x and y axes (axes PSP) and the speeds are equal (DGD = 0) as shown
in the figure in case (a). Indeed, the fiber geometry and asymmetry is due to birefringence have different indices
of refraction for both PSP's. This leads to different speeds for both polarozations axes as shown in the figure in
the case (b). The speed of light in a material depends on the refraction index of the material, as defined by the
following equation [24].
𝑣𝑥 =
𝑐
𝑛 𝑥
= 𝑣𝑦 =
𝑐
𝑛 𝑦
(4) 𝑣𝑥 =
𝑐
𝑛 𝑥
< 𝑣𝑦 =
𝑐
𝑛 𝑦
(5)
X X The fast asix
nx = ny nx> ny
ny ny
Y The slow asix Y
a) Ideal fiber optic b) Real fiber optic
Fig.3 Shows the DGD due to birefringence for both ideal fibre optic and real fibre optic
PSP axes are not uniform along the entire length of the fiber, PSP axes can rotate accordingly there will be
changes in the polarization orientation of the PSP, fashions pairing occurs between the fast axis and the slow
PSP, which affects the DGD. Leading causes of DGD includes the fiber produced with low quality, fiber
geometry not circular heart, the air present in the fiber, the impurities in the fiber, the pressures of the external
and internal exercised in fiber links between fibers, splices, temperature changes and pairing mode. PMD is not
static and can change and because fiber installed and may change over time. Change of DGD that depends on
the length of the wave is known as the second order PMD [25].
1.3Probability distribution
DGD is a function of the fiber birefringence and varies randomly along the fiber. As a result, DGD for a given
wavelength in a given time is a random variable.
Since DGD appears as a random event, probability that DGD event exceed the value x can be found via the
integral distribution of Maxwell-given by the following equation. Often it may happen that the value of DGD
exceed the maximum value tolerated by the recipient (DGDmax) which causes communication error bits [26].
DGDmax is defined as:
𝑝𝑟 ∆𝜏 𝐷𝐺 =
32
𝜋2 ∙
∆𝜏 𝐷𝐺
2
∆𝜏 𝐷𝐺
2 𝑒𝑥𝑝 −
4∆𝜏 𝐷𝐺
2
𝜋 ∆𝜏 𝐷𝐺
2 (6)
where𝑝𝑟 ∆𝜏 𝐷𝐺 =Maxwell probability distribution for a given wavelength
∆𝜏 𝐷𝐺 = DGD
∆𝜏 𝐷𝐺 = 𝐷𝐺𝐷 𝑎𝑣𝑒𝑟𝑎𝑔𝑒
DGDmax represents the value of DGD that the transceiver must tolerate that the maximum degradation of
sensitivity to be no more than 1 dB. DGD probability that event occur in a fiber is expressed by the following
equation where x is represented by the DGDmax:
𝑝𝑟(𝜟𝜏 𝐷𝐺 ≥ 𝑥) = 1 − 𝑝𝑟 (𝜟𝜏 𝐷𝐺 ) ⅆ𝜟𝜏 𝐷𝐺
𝑥
0
(7)
where𝑝𝑟(𝜟𝜏 𝐷𝐺 ≥ 𝑥)DGD is the probability that the event be greater than the value of x.
Report DGDmax to PMDtot (DGD on a link) can be referred to as the safety factor (SF). The safety factor is a
simple method to represent the probability of events that cause DGD communication concerns.
𝑆𝐹 =
𝐷𝐺 𝐷 𝑚𝑎𝑥
𝑃𝑀𝐷𝑡𝑜𝑡
(8)
where 𝑆𝐹 = safety factor
𝐷𝐺𝐷 𝑚𝑎𝑥 = maximum DGD on a link to a specific wavelength
𝑃𝑀𝐷𝑡𝑜𝑡 = the total PMD in a link to a specific wavelength
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1.4The total PMD link
The components of a fiber link can contribute to the total PMD-in link. PMD of components such as WDM,
DWDM, CWDM, DCM (except for DCM which uses DCF) and optical amplifiers is deterministic (DGD no
time varies but can vary depending on the wavelength). Specifications for these components should be reviewed
and PMD values should be included in calculating the budget of the link PMD's. However, if it is using the same
fiber and any other element PMD, to calculate the PMD used the first two formulas. In the links comprised of
different fiber types of calculations performed by the last formula [27].
𝑃𝑀𝐷𝑓 = 𝑃𝑀𝐷 𝑄 × 𝐿 (9)
𝑃𝑀𝐷𝑓 = 𝑃𝑀𝐷 𝑚𝑎𝑥 × 𝐿 (10)
𝑃𝑀𝐷𝑓 = 𝐿𝑖 𝑃𝑀𝐷 𝑄ⅈ
2
𝑖
1∕2
(11) 𝑃𝑀𝐷𝑡𝑜𝑡 = 𝐿𝑖 𝑃𝑀𝐷 𝑚ⅈ
2
𝑖
1∕2
(12)
II. Some Simulation Of PMD
2. Polarization dependent loss
Loss of polarization dependent loss of the optical signal in a fiber components or due to the change of the
polarity of the signal. Because the laser light is polarized to some degree and differ substantially randomly along
the fiber, this effect can cause signal strength fluctuations in the making. Maximum power fluctuations optical
signals are represented by PDL and defined as the ratio of maximum output transmitance to minimum
retirement transmitance for all the possible states of polarization at the entrance when a constant force at the
entrance [28].
𝑃𝐷𝐿 = 10𝑙𝑜𝑔
𝑇𝑟𝑚𝑎𝑥
𝑇 𝑟𝑚𝑖𝑛
(13)
Transmitance defined as the ratio of output optical power to the optical input power and calculated by the
formula:
𝑇𝑡 =
𝑃 𝑜𝑢𝑡
𝑃 𝑖𝑛
(14)
Fig.4 The system where made simulations to see the system's performance compared to fibre with different
PMD coefficient.
In the above system is the system's performance compared to fiber with different PMD coefficient. In the fiber
with PMD coefficient equal to 2ps / √km which supports transmission speeds at 2.5 Gbitps a length greater than
100 km. This simulation examines the effect of fiber PMD for new and old in different distance. Each iteration
uses PMD different and random. Extinction, chromatic dispersion and nonlinear effects are not included so that
all signal distortions caused only by PMD. For different combinations of PMD, bit rate and different lengths of
fiber look eye diagram form.
The first simulation : L=1000km BR=2.5 Gbps PMDc = 2ps/ km
6. The Effect Of PMD (Polarization Mode Dispersion) The Fibers Of New And Old In Different…
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(a)
(b)
(c)
Fig. 5 Shows the first simulationto the old fibre optic for bite rate 2.5Gbps where waveform is in contest (a), the
power is in content (b) and electrical signal is in content (c).
The second simulation : L=1000km BR=10 Gbps PMDc = 2ps/ km
(a)
7. The Effect Of PMD (Polarization Mode Dispersion) The Fibers Of New And Old In Different…
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(b)
(c)
Fig. 6 Shows the second simulation to the old fibre optic for bite rate 10Gbps where waveform is in contest (a),
the power is in content (b) and electrical signal is in content (c).
The third simulation : L=10000km BR=10 Gbps PMDc = 0.1ps/ km
(a)
(b)
8. The Effect Of PMD (Polarization Mode Dispersion) The Fibers Of New And Old In Different…
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(c)
Fig. 7 Shows the third simulation to the new fibre optic for PMDc = 0.1ps/ km where waveform is in contest
(a), the power is in content (b) and electrical signal is in content (c).
PDL also can be defined as output optical power when the input power is constant for all states of polarization.
PDL = 10log
Pmax
Pmin
(15)
Polarization dependent losses also depend on the wavelength PMD although not depend on the speed of
transmission.
III. Conclusion
The rapid stride toward high-speed transmission at 40 Gb/s and beyond has stimulated extensive research efforts
on PMD. Is important covered the fundamental understanding of the PMD effect and its impact on optical
transmission systems. The statistical nature of PMD, the development of PMD emulators, and the mixture of
PMD with other impairments, e.g., polarization-dependent losses (PDL) and nonlinearity, were discussed. The
analysis of the tolerance of different modulation formats to PMD effects also received a great attention. The
reason is that modulation formats with smaller duty cycle tend to have larger bandwidth and therefore they are
more sensitive to high-order PMD. Notice that the impairments in PMD compensated systems are mainly
caused by high-order PMD. In general, the smaller the bandwidth of the modulation formats, the more
improvement of PMD tolerance can be obtained after PMD compensation.
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