Free space optics (FSO) uses visible light communication or infrared light to transmit data wirelessly over the air. It works by using a laser or LED light source to transmit data to a photodetector. FSO systems provide high-speed fiber-like bandwidth without the need for cables or licensing. Common applications include extending metropolitan networks, providing last mile access, connecting enterprise buildings, and cellular backhaul. FSO experiences less attenuation than radio frequencies and can transmit data at speeds up to 10 Gbps.
Free Space Optics (FSO) communications, also called Free Space Photonics (FSP) or Optical Wireless, refers to the transmission of modulated visible or infrared (IR) beams through the atmosphere to obtain optical communications. Like fiber, Free Space Optics (FSO) uses lasers to transmit data, but instead of enclosing the data stream in a glass fiber, it is transmitted through the air. Free Space Optics (FSO) works on the same basic principle as Infrared television remote controls, wireless keyboards
FSO networks under turbulence - Northumbria University 2013 Research ConferenceJoaquin Perez
FSO networks: understanding route diversity under turbulence phenomena towards reliable FSO mesh networks design.
In last mile extensions of MANs, wireless mesh networks are multi-hop networks being used as backbone networks connecting end-users with the access points connected to the Internet. Wireless mesh networks are an attractive option over optical fibres because of their ease of installation and cost effectiveness of deployment[1]. Moreover, Free Space Optics (FSO) technology is an attractive option for use in mesh networks [2, 3]. However, time-variant influence of the atmosphere in FSO links that introduces one of the main drawbacks [4]. In order to overcome the turbulence induced fading in FSO systems, several techniques have been proposed These include: spatial transmitter/receiver diversity [5] [6]; adaptive beam forming [7]; wavelength diversity [8], multiple-beam communication [9], novel modulation techniques and hybrid RF/optical link scheme. Moreover, topology design and routing are essential tools for FSO mesh networks performance. The turbulence phenomena also influences in the topology and routing design of complex FSO networks, then route diversity techniques will improve the mesh network reliability [14]. For example, route diversity application within mesh optical networks deployed Tokyo provided interesting experiment results in [15]. This presentation will offer an overview of turbulence phenomena on FSO mesh networks from route diversity point of view.
References
[1] I. F. Akyildiz, X. Wang, and W. Wang, "Wireless mesh networks: a survey," Computer Networks, vol. 47, pp. 445-487, 2005.
[2] Z. Hu, P. Verma, and J. J. Sluss, "Improved reliability of free-space optical mesh networks through topology design," J. Opt. Netw., vol. 7, pp. 436-448, 2008.
[3] A. Kashyap, K. Lee, M. Kalantari, S. Khuller, and M. Shayman, "Integrated topology control and routing in wireless optical mesh networks," Computer Networks, vol. 51, pp. 4237-4251, 2007.
[4] Z. Ghassemlooy, W. Popoola, and S. Rajbhandari, Optical Wireless Communications : System and Channel Modelling with MATLAB: CRC Press 2012.
[5] S. M. Navidpour, M. Uysal, and M. Kavehrad, "BER performance of free-space optical transmission with spatial diversity," IEEE Trans. Wireless Commun., vol. 6, pp. 2813-2819, Aug 2007.
[6] H. Moradi, H. H. Refai, and P. G. LoPresti, "Switch-and-stay and switch-and-examine dual diversity for high-speed free-space optics links," IET Optoelectron, vol. 6, pp. 34-42, 2012.
[7] R. K. Tyson, "Bit-error rate for free-space adaptive optics laser communications," J. Opt. Soc. Am. A:, vol. 19, pp. 753-758, Apr 2002.
[8] V. Weerackody and A. R. Hammons, "Wavelength Correlation in Free Space Optical Communication Systems," in Proceedings of IEEE Military Communications Conference 2006, 2006, pp. pp. 1-6.
Free-space optical communication is an optical communication technology that uses light propagating in free space to wirelessly transmit data for telecommunications or computer networking. It is a technology that can be installed license-free worldwide and can be installed in less than a day. A technology that offers a fast, high ROI. There is no Frequency License Required in it.
Free Space Optics (FSO) communications, also called Free Space Photonics (FSP) or Optical Wireless, refers to the transmission of modulated visible or infrared (IR) beams through the atmosphere to obtain optical communications. Like fiber, Free Space Optics (FSO) uses lasers to transmit data, but instead of enclosing the data stream in a glass fiber, it is transmitted through the air. Free Space Optics (FSO) works on the same basic principle as Infrared television remote controls, wireless keyboards
FSO networks under turbulence - Northumbria University 2013 Research ConferenceJoaquin Perez
FSO networks: understanding route diversity under turbulence phenomena towards reliable FSO mesh networks design.
In last mile extensions of MANs, wireless mesh networks are multi-hop networks being used as backbone networks connecting end-users with the access points connected to the Internet. Wireless mesh networks are an attractive option over optical fibres because of their ease of installation and cost effectiveness of deployment[1]. Moreover, Free Space Optics (FSO) technology is an attractive option for use in mesh networks [2, 3]. However, time-variant influence of the atmosphere in FSO links that introduces one of the main drawbacks [4]. In order to overcome the turbulence induced fading in FSO systems, several techniques have been proposed These include: spatial transmitter/receiver diversity [5] [6]; adaptive beam forming [7]; wavelength diversity [8], multiple-beam communication [9], novel modulation techniques and hybrid RF/optical link scheme. Moreover, topology design and routing are essential tools for FSO mesh networks performance. The turbulence phenomena also influences in the topology and routing design of complex FSO networks, then route diversity techniques will improve the mesh network reliability [14]. For example, route diversity application within mesh optical networks deployed Tokyo provided interesting experiment results in [15]. This presentation will offer an overview of turbulence phenomena on FSO mesh networks from route diversity point of view.
References
[1] I. F. Akyildiz, X. Wang, and W. Wang, "Wireless mesh networks: a survey," Computer Networks, vol. 47, pp. 445-487, 2005.
[2] Z. Hu, P. Verma, and J. J. Sluss, "Improved reliability of free-space optical mesh networks through topology design," J. Opt. Netw., vol. 7, pp. 436-448, 2008.
[3] A. Kashyap, K. Lee, M. Kalantari, S. Khuller, and M. Shayman, "Integrated topology control and routing in wireless optical mesh networks," Computer Networks, vol. 51, pp. 4237-4251, 2007.
[4] Z. Ghassemlooy, W. Popoola, and S. Rajbhandari, Optical Wireless Communications : System and Channel Modelling with MATLAB: CRC Press 2012.
[5] S. M. Navidpour, M. Uysal, and M. Kavehrad, "BER performance of free-space optical transmission with spatial diversity," IEEE Trans. Wireless Commun., vol. 6, pp. 2813-2819, Aug 2007.
[6] H. Moradi, H. H. Refai, and P. G. LoPresti, "Switch-and-stay and switch-and-examine dual diversity for high-speed free-space optics links," IET Optoelectron, vol. 6, pp. 34-42, 2012.
[7] R. K. Tyson, "Bit-error rate for free-space adaptive optics laser communications," J. Opt. Soc. Am. A:, vol. 19, pp. 753-758, Apr 2002.
[8] V. Weerackody and A. R. Hammons, "Wavelength Correlation in Free Space Optical Communication Systems," in Proceedings of IEEE Military Communications Conference 2006, 2006, pp. pp. 1-6.
Free-space optical communication is an optical communication technology that uses light propagating in free space to wirelessly transmit data for telecommunications or computer networking. It is a technology that can be installed license-free worldwide and can be installed in less than a day. A technology that offers a fast, high ROI. There is no Frequency License Required in it.
Descripcion de la tecnologia y sistemas de luz para transmitir señales
Sistemas de transmision por fibra optica, equipos de fibra optica para transmision inalambrica
Descripcion de la tecnologia y sistemas de luz para transmitir señales
Sistemas de transmision por fibra optica, equipos de fibra optica para transmision inalambrica
Cryptography is the science of using mathematics to encrypt and decrypt data.
Cryptography enables you to store sensitive information or transmit it across insecure networks so that it cannot be read by anyone except the intended recipient.
This PPT explains about the term "Cryptography - Encryption & Decryption". This PPT is for beginners and for intermediate developers who want to learn about Cryptography. I have also explained about the various classes which .Net provides for encryption and decryption and some other terms like "AES" and "DES".
Free Space Optics (FSO) communications, also called Free Space Photonics (FSP) or Optical Wireless, refers to the transmission of modulated visible or infrared (IR) beams through the atmosphere to obtain optical communications. Like fiber, Free Space Optics (FSO) uses lasers to transmit data, but instead of enclosing the data stream in a glass fiber, it is transmitted through the air. Free Space Optics (FSO) works on the same basic principle as Infrared television remote controls, wireless keyboards or wireless Palm® devices.
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.
Free space optics known as (FSO) is very popular now days this is because of increased demand for cheaper, faster and most important affordable internet. So many research scientists have taken the great interest in this field. FSO uses laser for transmitting data at the speed capable of reaching 2.5 Gbps through the air. And its systems use invisible infrared laser light wavelengths in the 780 nm to 1600 nm range. This article explains the FSO security, the transmission characteristics and also its challenges; although Free Space Optic systems can be a better solution for the needs of some broadband networking, there are limitations of bad climatic conditions that influence its performance such as fog, snow and too much rain can shut down the network. The performance of FSO is measured by Bit Error Rates (BER).
Establishment Network by Using FSO Link Based on MD Code for Hybrid SCM-SAC-O...IJECEIAES
Since the wireless systems are working under nature environments and influenced by turbulence, weather in Iraq that leads to extended amount of fading signal, dissipation or attenuation. Basic “hybrid Subcarrier Multiplying Spectral Amplitude Coding (SCM-SAC) of Optical Code Division Multiple Access (OCDMA)" indoor or outdoor optical system depends on generally “Multi-Diagonal (MD)" security code by using optical space known as “Free Space Optic (FSO)" that was proposed in this work. It is found that the mention hybrid wireless systems can be used in operating mesh networks. The main proposed idea of hybrid optical technique was analyzed and simulated by normally taking into simulation account that the directly effecting by rain and haze attenuations. In addition, there are mention and description for atmospheric effects, FSO mesh network, modulation scheme, simulation, and the data security. From simulation results, the hybrid system using MD code produces reduced “bit-error rate (BER)" at heavy storm rain to distance or range of 500 m and at drizzle rain up to 2500 m range. And also investigates the performance of using the proposed system with radio over fiber (RoF) for UWB signals through indoor propagation in building applications of wireless channel.
Optical Wireless Communication (OWC) has attracted the researchers as an alternative broadband technology for wireless communication. In OWC optical beams are used to transport data through atmosphere or even vacuum. We have proposed an OWC model and analyze the transmission performance of OW channel for indoor/ outdoor application. The performance has been judged on the basis of key parameters like BER and OSNR. A theoretical model has also been presented and validated by the simulation results. The proposed OWC channel was simulated in Optisystem which is a powerful tool of Optical communication System
Free Space Optics (FSO), also known as Optical Wireless Communication or Laser Communication, is a communication technology that employs beams of light to transmit data through the air or free space. Unlike traditional wired or radio-frequency-based communication methods, FSO relies on the transmission of modulated laser or infrared beams to establish high-speed data links between two points without the need for physical cables.
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.
This report gives the viewers a broad description about using a light wave generated from a typical LED's or LASER source for an effective communication.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
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CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptx
Report on Free space optics
1. THEJESH 1
FREE SPACE OPTICS
TABLE OF CONTENTS.
1. Introduction....................................................4
2. History of FSO……………………………....4
3. Working of FSO……………………………..5
4. Method of operation…………………….5
5. Application……………………...............7
6. Optical transmission…………………………6
7. Wireless speed of light with EDFA………....7
8. Conclusion……………………………………8
9. References…………………………………….9
LIST OF FIGURES.
1. 2. FSO Block diagram…………….6
2. 3. Incident Laser beam……….....6
3. FSO internal structure………………5
4. Data passes through Layer……….7
5. Ethernet Format……………………..8
6. He-Ne laser tube……………………….5
7. Fso internal structure………………….6
8. Transmission vs Wavelength graph…...7
9. Architecture of EDFA………………....8
2. THEJESH 2
FREE SPACE OPTICS
1.INTRODUCTION
Free-space optical communication (FSO) systems (in space and inside the atmosphere)
have developed in response to a growing need for high-speed and tap-proof
communication systems. Links involving satellites, deep-space probes, ground stations,
unmanned aerial vehicles (UAVs), high altitude platforms (HAPs), aircraft, and other
nomadic communication partners are of practical interest. Moreover, all links can be
used in both military and civilian contexts. FSO is the next frontier for net-centric
connectivity, as bandwidth, spectrum and security issues favor its adoption as an
adjunct to radio frequency (RF) communications.
While fixed FSO links between buildings have long been established and today form a
separate commercial product segment in local and metropolitan area networks. the
mobile and long-range applications of this technology are aggravated by extreme
requirements for pointing and tracking accuracy because of the small optical beam
divergences involved.
2. HISTORY OF FREE SPACE OPTICS
Optical communication has been used thousand of year. In 1880,Alexander Graham
Bell and his assistant Charles summer tainter created photophone at Bell's newly
established laboratory in washington,Dc. Bell patented photophone, which modulated
light reflect from the sun with a voice signal and transmitted that across the free space
to a solid state dectecor.thus was born FSO(free space optics). On june 3,1880 Bell
made world’s first wireless telephone,which was used between two building at distance
213 meter.
In 1962, Dr. Erahard kube was developed first HeNe laser(HeliumNeon laser) at Bell
Telephone laboratories.
In 1962, Dr. Erahard kube was developed first HeNe laser(HeliumNeon laser) at Bell
Telephone laboratories. HeNe laser is a type of laser whose gain medium consists of a
mixture of Helium and Neon(10:1)inside a small bore capillary tube,usually excited
3. THEJESH 3
FREE SPACE OPTICS
byBy a DC electrical discharge,pressure maintain inside the tube is 1mm of Hg And
emitted the light at 1.15 m in the infrared specturm, was first gas laser.
FIGURE1.1 –He-Ne LASER TUBE
3.HOW FREE SPACE OPTICS WORK.
FSO technology is surprisingly simple. It's based on connectivity between FSO-based
optical wireless units, each consisting of an optical transceiver with a transmitter and a
receiver to provide full-duplex (bi-directional) capability. Each optical wireless unit
uses an optical source, plus a lens or telescope that transmits light through the
atmosphere to another lens receiving the information. At this point, the receiving lens
or telescope connects to a high-sensitivity receiver via optical fiber. This FSO
technology approach has a number of advantages: Requires no RF spectrum licensing.
Is easily upgradeable, and its open interfaces support equipment from a variety of
vendors, which helps enterprises and service providers protect their investment in
embedded telecommunications infrastructures. Requires no security software upgrades.
Is immune to radio frequency interference or saturation. Can be deployed behind
windows, eliminating the need for costly rooftop rights.
.
4. THEJESH 4
FREE SPACE OPTICS
FIGURE 1.2–FSO INTERNAL STRUCTURE
4. OPTICAL TRANSMISSION
By its very nature, remote sensing implies that the source being measured is some
distance away from the optical receiver. The atmospheric path between the source and
receiver will attenuate the sources signature and is likely to change its spectral shape.
These changes have important implications for developing remote sensing systems and
interpreting their data.
FIGURE 4.5 –TRANSMISSION VS. WAVELENGTH.
5. SCINTILLATION
5. THEJESH 5
FREE SPACE OPTICS
Performance of many laser communications systems is adversely affected by
scintillation on bright sunny days. Through a large aperture receiver, widely spaced
transmitters, finely tuned receive filtering, and automatic gain control, downtime due
to scintillation can be avoided.
6.FSO :WIRELESS AT THE SPEED OF LIGHT
Optical wireless, based on FSO-technology, is an outdoor wireless product category
that provides the speed of fiber, with the flexibility of wireless. It enables optical
transmission at speeds of up to 1.25 Gbps and, in the future, is capable of speeds of 10
Gbps using WDM.This is not possible with any fixed wireless or RF technology.
Optical wireless also eliminates the need to buy expensive spectrum (it requires no
municipal license approvals worldwide), which further distinguishes it from fixed
wireless technologies. Moreover, FSO technology’s narrow beam transmission is
typically two meters versus 20 meters and more for traditional, even newer radio-based
technologies such as millimeter-wave radio. Optical wireless products' similarities with
conventional wired optical solutions enable the seamless integration of access networks
with optical core networks and helps to realize the vision of an all-optical network
4.HOW FREE SPACE OPTICS (FSO) CAN HELP YOU.
FSO’s freedom from licensing and regulation translates into ease, speed and low cost
of deployment. Since Free Space Optics (FSO) transceivers can transmit and receive
through windows, it is possible
to mount Free Space Optics (FSO) systems inside buildings, reducing the need to
compete for roof space, simplifying wiring and cabling, and permitting Free Space
Optics (FSO) equipment to operate in a very favorable environment. The only essential
requirement for Free Space Optics (FSO) or optical wireless transmission is line of sight
between the two ends of the link.
For Metro Area Network (MAN) providers the last mile or even feet can be the most
daunting. Free Space Optics (FSO) networks can close this gap and allow new
customers access to high-speed MAN’s. Providers also can take advantage of the
6. THEJESH 6
FREE SPACE OPTICS
reduced risk of installing an Free Space Optics (FSO) network which can later be
redeployed.
5.THE MARKET. WHY FREE SPACE OPTICS(FSO).
The global telecommunications network has seen massive expansion over the last few
years. First came the tremendous growth of the optical fiber long-haul, wide-area
network (WAN), followed by a more recent emphasis on metropolitan area networks
(MANs). Meanwhile, local area networks (LANs) and gigabit ethernet ports are being
deployed with a comparable growth rate. In order for this tremendous network capacity
to be exploited, and for the users to be able to utilize the broad array of new services
becoming available, network designers must provide a flexible and cost-effective
means for the users to access the telecommunications network. Presently, however,
most local loop network connections are limited to 1.5 Mbps (a T1 line). As a
consequence, there is a strong need for a high-bandwidth bridge (the “last mile” or “first
mile”) between the LANs and the MANs or WANs.
Free Space Optics (FSO) systems represent one of the most promising approaches for
addressing the emerging broadband access market and its “last mile” bottleneck. Free
Space Optics (FSO) systems offer many features, principal among them being low start-
up and operational costs, rapid deployment, and high fiber-like bandwidths due to the
optical nature of the technology.
4.METHOD OF OPERATION IN FSO.
FSO systems operate very much like a fiber optic connection using a cable. Themain
difference being the attenuation in a cable is known and controllable, whereasin a FSO
link that uses theatmosphere as the media, the exact attenuation of the link can vary by
the second and is unknowable. To make this type of system work a device known as a
laser diode , photon detector reciver, digital data.
19
7. THEJESH 7
FREE SPACE OPTICS
FIGURE 1.2 – FSO BLOCK DIAGRAM.
FIGURE 1.3 –INCIDENT LASER BEAM.
It consist the many lenses. Single element lens that focuses light to detector. In fact
some unique application require even more exotic optical front ends, such as in
ACTIVE system designs where the optical assembly both project project a light source
such as a laser to illuminate the object and also receives the resultant photons that are
reflected from the object.
5. SCATTERING IN FSO.
8. THEJESH 8
FREE SPACE OPTICS
light scattering by atmospheric gases and molecules will attenuate optical signals
between the source and receiver by redirecting photons from their propagation paths.
These same phenomena can also increase the background signals observed by a remote
sensing system by redirecting solar radiation along the propagation path towards the
receiver.
6.FREE SPACE OPTICS (FSO) APPLICATION.
1.Metro network extensions:- FSO is used to extend existing metropolitan area
fiberings to connect new networks from outside.
2.Last mile access:- FSO can be used in high-speed links to connect end users with
ISPs.
3.Enterprise connectivity:- The ease in which FSO can be installed makes them a
solution for interconnecting LAN segments, housed in buildings separated by public
streets.
4.Fiber backup:- FSO may be deployed in redundant links to backup fiber in place of
a second fiber link.
5.Backhaul:- Used to carry cellular telephone traffic from antenna towers back to
facilities into the public switched telephone networks.
6.SERVICE TYPES AND NETEORK TRANSMISSION OF FSO.
Two basic service types (switching technologies)
1.Connection-oriented
2.Connectionless
Connection-oriented -Based on circuit switching (setup, connect, tear-down)
9. THEJESH 9
FREE SPACE OPTICS
Example: Public Switching Telephone Network (PSTN) Originally only supported
voice Not good for bursty traffic Connectionless Based on sending datagrams
Examples: Packet, massage, burst switching Improves bandwidth and network
utilization .
7.MAC Sub layer.
In Standard Ethernet, the MAC sublayer governs the operation of the access method.
It also frames data received from the upper layer and passes them to the physical layer.
8.Frame Format.
The Ethernet frame contains seven fields: preamble, SFD, DA, SA, length or type of
protocol data unit (PDU), upper-layer data, and the CRC Ethernet does not provide any
Fig.How Data Passes Through Layers.
Each computer has a layered protocols
10. THEJESH 10
FREE SPACE OPTICS
mechanism for acknowledging received frames, making it what is known as an
unreliable medium. Acknowledgments must be implemented at the higher layers.
9.FREE SPACE OPTICS (FSO) APPLICATION.
1.Metro network extensions:- FSO is used to extend existing metropolitan area fiberings
to connect new networks from outside.
2.Last mile access:- FSO can be used in high-speed links to connect end users with
ISPs.
3.Enterprise connectivity:- The ease in which FSO can be installed makes them a
solution for interconnecting LAN segments, housed in buildings separated by public
streets.
Fig-Ethernet frame.
Fig-Ethernet frame.
11. THEJESH 11
FREE SPACE OPTICS
4.Fiber backup:- FSO may be deployed in redundant links to backup fiber in place of a
second fiber link.
5.Backhaul:- Used to carry cellular telephone traffic from antenna towers back to
facilities into the public switched telephone networks.
10.CONCLUSION.
FSO enables optical transmission of voice video and data through air at very high rates.
It has key roles to play as primary access medium and backup technology. Driven by
the need for high speed local loop connectivity and the cost and the difficulties of
deploying fiber, the interest in FSO has certainly picked up dramatically among service
providers world- wide . Instead of fiber coaxial systems, fiber laser systems may turn
out to be the best way to deliver high data rates to your home. FSO continues to
accelerate the vision of all optical networks cost effectively, reliably and quickly with
freedom and flexibility of deployment.
12. THEJESH 12
FREE SPACE OPTICS
11.REFERENCES.
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2. Keshav, S. An Engineering Approach to Computer Networking. Reading,MA:
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3. Kumar A., Manjunath, D., and Kuri, 1. Communication Networking. San
Francisco, CA: Morgan, Kaufmans, 2004.
4. Data communication and networking.Behrouz A.Forouzan.
5. 1] .V. W. S. Chan, “Coherent optical space communications system:
Architecture and technology issues,” in SPIE Control Communication
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, NJ: Prentice Hall, 2000.