As an unprecedented opportunity to dramatically increase the bandwidth capacity, WDM (Wavelength Division Multiplexing) technology is an ideal solution to get more bandwidth and lower cost in nowaday telecommunications networks. By virtue of fame, WDM becomes a household word now. Yet, most of the time, we only know what is "WDM" but do not really know WDM technology. Actually, there are various of terminologies used in WDM that are always a headache for us.
Course Wave Division Multiplexing (CWDM): TechNet Augusta 2015AFCEA International
August 24, 2015
Dennis Troxel
Transition Networks
This Technology overview outlines the technology of Course Wave Division Multiplexing including real world government application examples to demonstrate the value of:
A) Overcoming Fiber Exhaustion
B) Increasing Fiber Bandwidth capacity
C) Providing Multiple Services over existing Fiber Pairs
What does WDM (Wavelength Division Multiplexing )stand for?HYC Co., Ltd
This article will include these subject.
What does WDM stand for?
The basic structure of WDM system
Advantages of WDM technology
What does Mux and Demux stand for?
The difference between WDM and optical splitter
The indicators that affect the WDM devices
How to understand the O, E, S, C, L, U band
What does CWDM stand for vs. DWDM, FWDM, LWDM, MWDM?
HYC can provide customers with a one-stop optical network device and low-cost optical communication products, supplying a range of WDM products. HYC Co.,Ltd(HYC)is a national Hi-tech optoelectronics company engaged in R&D, manufacture and marketing of fiber optical products. Providing professional product and service for fiber connectivity,WDM, PLC splitter and high density datacom cabling. HYC products and solutions widely applied in 4G/5G, Data Center and Cloud Computing industry etc.
Performance analysis of dwdm based fiber optic communication with different m...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
How to use WDM technology to expand fiber capacity.pdfHYC Co., Ltd
An article introduces all about WDM technology, including how does WDM work, what's mux and demux, cwdm vs dwdm, what does optical add-drop multiplexer stand for, wdm bands, wdm technology, wdm applications. How to use WDM technology to expand fiber capacity?
Course Wave Division Multiplexing (CWDM): TechNet Augusta 2015AFCEA International
August 24, 2015
Dennis Troxel
Transition Networks
This Technology overview outlines the technology of Course Wave Division Multiplexing including real world government application examples to demonstrate the value of:
A) Overcoming Fiber Exhaustion
B) Increasing Fiber Bandwidth capacity
C) Providing Multiple Services over existing Fiber Pairs
What does WDM (Wavelength Division Multiplexing )stand for?HYC Co., Ltd
This article will include these subject.
What does WDM stand for?
The basic structure of WDM system
Advantages of WDM technology
What does Mux and Demux stand for?
The difference between WDM and optical splitter
The indicators that affect the WDM devices
How to understand the O, E, S, C, L, U band
What does CWDM stand for vs. DWDM, FWDM, LWDM, MWDM?
HYC can provide customers with a one-stop optical network device and low-cost optical communication products, supplying a range of WDM products. HYC Co.,Ltd(HYC)is a national Hi-tech optoelectronics company engaged in R&D, manufacture and marketing of fiber optical products. Providing professional product and service for fiber connectivity,WDM, PLC splitter and high density datacom cabling. HYC products and solutions widely applied in 4G/5G, Data Center and Cloud Computing industry etc.
Performance analysis of dwdm based fiber optic communication with different m...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
How to use WDM technology to expand fiber capacity.pdfHYC Co., Ltd
An article introduces all about WDM technology, including how does WDM work, what's mux and demux, cwdm vs dwdm, what does optical add-drop multiplexer stand for, wdm bands, wdm technology, wdm applications. How to use WDM technology to expand fiber capacity?
What is WDM(wavelength division multiplexer) and how does it work.pdfHYC Co., Ltd
As technology continues to advance, the demand for more data and faster speeds increases. One way to meet these demands is by using Wavelength Division Multiplexing (WDM) technology, which allows for the expansion of a network's capacity by increasing the amount of data that can be transmitted over a single fiber optic cable. In this article, we'll explore how WDM works and the benefits it can bring to your network.
In fibre optic communications Wavelength Division Multiplexing or WDM is a technology which multiplexes a number of optical carrier signals onto a single optical fibre by using different wavelengths of laser light. This technique enables us to get high bit rate and efficient use of fibre bandwidth. WDM allows communication in both the directions in the fiber cable.
In WDM, the optical signals from different sources or (transponders) are combined by a multiplexer, which is essentially an optical combiner. They are combined so that their wavelengths are different. The combined signal is transmitted via a single optical fiber strand. At the receiving end, a demultiplexer splits the incoming beam into its components and each of the beams is send to the corresponding receivers.
A Beginner's Guide to Wavelength Division Multiplexing (WDM)VERSITRONINC
Wavelength division multiplexing or WDM has gained immense traction over the last few years. It has been the preferred choice of technology for transporting massive data in the form of light signals over a fiber cable. By doing so, it maximizes fiber network capacity and avoids excess wiring. Are you intrigued to know more about WDM technology?
you can be friend with me on orkut
"mangalforyou@gmail.com" : i belive in sharing the knowledge so please send project reports ,seminar and ppt. to me .
In WDM(Wavelength Division Multiplexing) system, CWDM and DWDM are two main WDM technologies with different wavelength patterns, capabilities, costs, and applications. What‘’s the difference between CWDM and DWDM? What are their respective benefits? How do they work and how to use them? A brief introduction to show you!
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...SOFTTECHHUB
The choice of an operating system plays a pivotal role in shaping our computing experience. For decades, Microsoft's Windows has dominated the market, offering a familiar and widely adopted platform for personal and professional use. However, as technological advancements continue to push the boundaries of innovation, alternative operating systems have emerged, challenging the status quo and offering users a fresh perspective on computing.
One such alternative that has garnered significant attention and acclaim is Nitrux Linux 3.5.0, a sleek, powerful, and user-friendly Linux distribution that promises to redefine the way we interact with our devices. With its focus on performance, security, and customization, Nitrux Linux presents a compelling case for those seeking to break free from the constraints of proprietary software and embrace the freedom and flexibility of open-source computing.
Essentials of Automations: The Art of Triggers and Actions in FMESafe Software
In this second installment of our Essentials of Automations webinar series, we’ll explore the landscape of triggers and actions, guiding you through the nuances of authoring and adapting workspaces for seamless automations. Gain an understanding of the full spectrum of triggers and actions available in FME, empowering you to enhance your workspaces for efficient automation.
We’ll kick things off by showcasing the most commonly used event-based triggers, introducing you to various automation workflows like manual triggers, schedules, directory watchers, and more. Plus, see how these elements play out in real scenarios.
Whether you’re tweaking your current setup or building from the ground up, this session will arm you with the tools and insights needed to transform your FME usage into a powerhouse of productivity. Join us to discover effective strategies that simplify complex processes, enhancing your productivity and transforming your data management practices with FME. Let’s turn complexity into clarity and make your workspaces work wonders!
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
Generative AI Deep Dive: Advancing from Proof of Concept to ProductionAggregage
Join Maher Hanafi, VP of Engineering at Betterworks, in this new session where he'll share a practical framework to transform Gen AI prototypes into impactful products! He'll delve into the complexities of data collection and management, model selection and optimization, and ensuring security, scalability, and responsible use.
The Metaverse and AI: how can decision-makers harness the Metaverse for their...Jen Stirrup
The Metaverse is popularized in science fiction, and now it is becoming closer to being a part of our daily lives through the use of social media and shopping companies. How can businesses survive in a world where Artificial Intelligence is becoming the present as well as the future of technology, and how does the Metaverse fit into business strategy when futurist ideas are developing into reality at accelerated rates? How do we do this when our data isn't up to scratch? How can we move towards success with our data so we are set up for the Metaverse when it arrives?
How can you help your company evolve, adapt, and succeed using Artificial Intelligence and the Metaverse to stay ahead of the competition? What are the potential issues, complications, and benefits that these technologies could bring to us and our organizations? In this session, Jen Stirrup will explain how to start thinking about these technologies as an organisation.
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
Observability Concepts EVERY Developer Should Know -- DeveloperWeek Europe.pdfPaige Cruz
Monitoring and observability aren’t traditionally found in software curriculums and many of us cobble this knowledge together from whatever vendor or ecosystem we were first introduced to and whatever is a part of your current company’s observability stack.
While the dev and ops silo continues to crumble….many organizations still relegate monitoring & observability as the purview of ops, infra and SRE teams. This is a mistake - achieving a highly observable system requires collaboration up and down the stack.
I, a former op, would like to extend an invitation to all application developers to join the observability party will share these foundational concepts to build on:
zkStudyClub - Reef: Fast Succinct Non-Interactive Zero-Knowledge Regex ProofsAlex Pruden
This paper presents Reef, a system for generating publicly verifiable succinct non-interactive zero-knowledge proofs that a committed document matches or does not match a regular expression. We describe applications such as proving the strength of passwords, the provenance of email despite redactions, the validity of oblivious DNS queries, and the existence of mutations in DNA. Reef supports the Perl Compatible Regular Expression syntax, including wildcards, alternation, ranges, capture groups, Kleene star, negations, and lookarounds. Reef introduces a new type of automata, Skipping Alternating Finite Automata (SAFA), that skips irrelevant parts of a document when producing proofs without undermining soundness, and instantiates SAFA with a lookup argument. Our experimental evaluation confirms that Reef can generate proofs for documents with 32M characters; the proofs are small and cheap to verify (under a second).
Paper: https://eprint.iacr.org/2023/1886
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
Pushing the limits of ePRTC: 100ns holdover for 100 daysAdtran
At WSTS 2024, Alon Stern explored the topic of parametric holdover and explained how recent research findings can be implemented in real-world PNT networks to achieve 100 nanoseconds of accuracy for up to 100 days.
Do you know all these terminologies of wdm technology
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Table of Contents
Overview··········································································································· 3
Basic Terminologies of WDM··················································································· 3
WDM (Wavelength Division Multiplexing)································································· 3
CWDM (Coarse Wavelength Division Multiplexing)·······················································3
DWDM (Dense Wavelength Division Multiplexing)······················································· 4
WDM Transmission System····················································································· 4
Single Fiber Transmission····················································································· 4
Dual Fiber Transmission······················································································· 4
Upstream (Return) & Downstream (Forward)····························································· 5
WDM System Topologies························································································ 5
Network Topologies····························································································5
Ring Topology··································································································· 5
Node··············································································································6
Filtration Technologies Applied to WDM····································································· 6
Arrayed Waveguide Grating (AWG)··········································································6
Fiber Bragg Grating (FBG)·····················································································6
Thin Film Filter (TFF)··························································································· 7
WDM Equipment··································································································7
Mux (Multiplexer)······························································································ 7
DeMux (De-Multiplexer)······················································································ 7
OADM (Optical Add-Drop Multiplexer)····································································· 8
FWDM (Filter-Based Wavelength Division Multiplexer)··················································8
Compact WDM································································································· 8
Banded Skip Filters·····························································································8
Ports on WDM Equipment······················································································ 8
Common Port··································································································· 9
Express or Upgrade Port······················································································ 9
1310nm Port···································································································· 9
1550nm Port···································································································· 9
Monitor Port···································································································· 9
Do You Know All These
Terminologies of WDM
Technology?
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Parameters of WDM Systems···················································································10
Wavelengths···································································································· 10
Channel·········································································································· 10
Pass Band········································································································10
Insertion Loss··································································································· 11
Polarization Dependent Loss (PDL)·········································································· 11
Polarization Mode Dispersion (PMD)········································································11
Return Loss······································································································11
Passband Ripple································································································ 11
Isolation··········································································································12
Operation Temperature······················································································· 12
Storage Temperature·························································································· 12
Water Peak······································································································ 12
New Network Technologies Based on WDM·································································13
Wavelength Division Multiplexing-Passive Optical Network (WDM-PON)···························· 13
Optical Transport Network (OTN)············································································13
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Overview
As an unprecedented opportunity to dramatically increase the bandwidth capacity, WDM
(Wavelength Division Multiplexing) technology is an ideal solution to get more bandwidth and lower
cost in nowaday telecommunications networks. By virtue of fame, WDM becomes a household
word now. Yet, most of the time, we only know what is "WDM" but do not really know WDM
technology. Actually, there are various of terminologies used in WDM that are always a headache
for us. Now, let's see what are they.
Basic Terminologies of WDM
First of all, there are three basic terminologies you should clearly know.
WDM (Wavelength Division Multiplexing)
A technology that multiplexes a number of optical carrier signals onto a single optical fiber by using
different optical wavelengths (i.e., colors) of laser light. It breaks white light passing through fiber
optic cable into all the colors of the spectrum, much like light passed through a prism creates a
rainbow. Every wavelength carries an individual signal that does not interfere with the other
wavelengths.
CWDM (Coarse Wavelength Division Multiplexing)
CWDM is a specific WDM technology defined by the ITU (International Telecommunication Union)
in ITU-T G.694.2 spectral grids, using the wavelengths from 1270 nm to 1610 nm within a 20nm
channel spacing. It is a technology of choice for cost efficiently transporting large amounts of data
traffic in telecoms or enterprise networks.
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DWDM (Dense Wavelength Division Multiplexing)
DWDM is a specific WDM technology also defined by the ITU but in ITU-T G.694.1 spectral grids.
The grid is specified as frequency in THz, anchored at 193.1 THz, with a variety of specified channel
spacing from 12.5 GHz to 200 GHz, among which 100 GHz is common. In practice, DWDM frequency
is usually converted to wavelength. DWDM typically has the capability to transport up to 80
channels (wavelengths) in what is known as the Conventional band (C-band) spectrum, with all 80
channels in the 1550 nm region.
WDM Transmission System
When referring to fiber optic transmission in WDM system, you should know these:
Single Fiber Transmission
Single fiber, namely bi-directional communication on one single fiber. This system utilizes two
identical sets of wavelengths for both directions over a single fiber. Individual channels residing on
the single fiber system may propagate in either direction.
Dual Fiber Transmission
Dual fiber, namely comprised of two single fibers, one fiber is used for the transmit direction and
the other is used for the receive direction. In dual fiber transmission system, the same wavelength is
normally used in both the transmit and receive directions. The second fiber may serve as a backup
fiber as in a redundant system, or it may provide an optical path in the opposite direction.
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Upstream (Return) & Downstream (Forward)
The direction of a communication signal can be refered using these two terminologies. The
downstream direction is defined as communication originating at a service provider and sent to the
service user. Upstream is in the opposite direction.
WDM System Topologies
The topology in which WDM systems are used plays a key role in determining the extent to which
the WDM network is utilized. The related terminologies are:
Network Topologies
WDM products bring higher efficiency to fiber networks through multiple channel usage of fiber.
Networks are identified by their fiber layout or topology. Network topologies such as Mesh, Ring,
P2P (Point-to-Point), and P2MP (Point-to-Multipoint) will sometimes use WDM products particularly
designed for the network. So, it is important to understand the intended network use when
selecting WDM products. Entire networks are often comprised of several kinds of sub-network
topologies.
Ring Topology
In metropolitan area networks, infrastructures are generally organized over a ring topology. Ring
topology is a type of network topology consisting of a closed loop. Fiber ring networks are
comprised of a series of fiber spans that terminate at network nodes spread throughout the loop.
Each node in the ring will connect to two, and only two, adjacent nodes. Ring networks are often
dual fiber systems. Contrast ring topology with an unclosed, end-to-end or point-to-point fiber
span.
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Node
In network topology, a node is a termination of a single branch or multiple branches of the network.
A WDM network consists of a set of nodes, physically interconnected by optical fiber (the physical
topology), upon which a logical topology is overlaid by establishing lightpath interconnections
between the nodes. The use of WDM on the fiber side allows the node to be segmented or divided
into additional serving areas thus expanding the customer base and available bandwidth.
Filtration Technologies Applied to WDM
There are three competing filtration technologies applied to WDM. They are:
Arrayed Waveguide Grating (AWG)
AWG, including Athermal AWG (AAWG) and Thermal AWG (TAWG), is commonly used as optical
MUX/DeMUX in WDM systems. AAWG have equivalent performance to standard TAWG but require
no electrical power, software or temperature.
Fiber Bragg Grating (FBG)
FBGs are versatile wavelength filters for multiplexing and demultiplexing WDM signals. They also
can compensate for chromatic dispersion that can degrade the quality of the WDM signal in an
optical fiber.
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Thin Film Filter (TFF)
Thin film filters were adopted very early on and have been widely deployed since because they have
the unique attributes that meet the stringent requirements of optical communication systems. The
main advantage of thin film filters is its ability to achieve high accuracy in processing in small device
sizes when compared it to competing technologies.
WDM Equipment
To build a WDM system, these WDM equipment are required:
Mux (Multiplexer)
WDM multiplexer is a device that multiplexes or combines optical signals of different wavelengths
(colors) together on one single fiber.
DeMux (De-Multiplexer)
In contrast to multiplexer, DeMux is a device that
de-multiplexes or splits optical transmission
comprised of multiplexed wavelengths onto
individual fibers assigned to each wavelength.
Note: In today's market, there are CWDM
Mux/DeMux products and DWDM Mux/DeMux
products. These products have the Mux and DeMux
inside and comes in a package like 1RU 19"
rackmont, LGX box and ABS module etc.
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OADM (Optical Add-Drop Multiplexer)
OADM is a device used in WDM systems for multiplexing and routing different channels of light into
or out of a single fiber.
FWDM (Filter-Based Wavelength Division Multiplexer)
Filter-based Wavelength Division Multiplexer (FWDM) is a kind of WDM multiplexer based on the
Thin Film Filter (TFF) technology. FWDM combines or separates light at different wavelengths in a
wide wavelength range and is extensively used in EDFA, Raman amplifiers, and WDM optical
networks.
Compact WDM
As the name suggests, these are multi-channel WDM products that have relatively small footprints
so that they can provide more channels with a device footprint small enough to fit within a FOSC
(Fiber Optic Splice Closure), splice tray or splice holder. These products utilize a free-space multiple
bounce technology in which light reflects from each filter element directly onto the next filter
element instead of being collimated and launched into a fiber as in individual, discrete TFF
components. In addition, bend insensitive fiber permits the use of smaller housings for joining
(concatenating) individual TFFs into a multi-channel product.
Banded Skip Filters
Banded skip filters are used to build BWDM (Band WDM) products. These filters are TFFs that have
wide pass bands, which contain multiple channels. For example, DWDM Red/Blue C-band Filter is
used to separate or combine Red and Blue band wavelength signals in C-band DWDM systems and
high-power amplification systems. It is just like a regular FWDM, with the only difference that the
wavelengths are split in Red/Blue filter while bonded in WDM.
Ports on WDM Equipment
Ports on WDM equipment, do you really know their functions?
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Common Port
The connection point of a WDM product where combined channels appear. For a MUX product,
combined channels are transmitted from the common port. For a DEMUX, the combined channels
are received at the common port.
Express or Upgrade Port
For CWDM products, there will normally be either an upgrade or an express port, but not both. The
upgrade or express port on a CWDM Mux or DeMux is used to add, drop, or pass through additional
channels which enables the cascading of two CWDM Mux/DeMux modules, doubling the channel
capacity on the common fiber link.
For DWDM products, the purpose of an upgrade port is to be able to add, drop, or pass through
C-band DWDM channels not already in use, namely only channels that reside in the band 1530 –
1565 nm. If the DWDM product also has an express port, then that port is normally used for
additional channels residing outside the C-band, such as most of the CWDM channels.
1310nm Port
The 1310nm port is a wide band optic port added to other specific CWDM wavelengths in a module.
For example if an 8 channel CWDM is called out it may use wavelengths 1470 nm to 1610 nm and
request the 1310nm port. The 1310nm port is used in some legacy networks and sometimes as a
return path. If an existing legacy network is using 1310nm port and they have exhausted all fibers
and are looking for ways to increase their network capacity they can add in other CWDM
wavelengths on to the same fiber while still allowing the use of the 1310nm port. Meanwhile, it can
carry LR optics, LX optics etc.
1550nm Port
Similar to 1310nm port, allows a legacy 1550nm signal to pass and can carry ER optics, ZR optics, LX
optics, ZX optics etc.
Monitor Port
This port is used to monitor or test the power signal coming out of a Muxed CWDM or before it gets
demuxed from the signal coming through the fiber network usually at a 5% or less power level.
Generally, it can be connected with measurement or monitoring equipment, such as power meters
or network analyzers. Network administrators will use this to test of monitor if a signal has failed or
changed without having to interrupt the existing network.
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Parameters of WDM Systems
You should also know these parameters when operating a WDM system:
Wavelengths
Wavelength is the distance, measured in the direction of propagation, between two points of the
same phase in consecutive cycles of a wave. The wavelength λm of monochromatic light travelling
in a optical fiber is expressed:
λm = λ / n = v / f
λ = optical wavelength in a vacuum
n = the refractive index of the dielectric medium
v = phase velocity, given by c / n
c = the speed of light in a vacuum: 2.99792458 X 108 m/s
f = the optical frequency.
Note: In WDM practice, wavelengths such as the wavelength of a communications laser, the
wavelength specifications for optical filters, and the wavelengths of optical transmission channels
over fiber are all given as λ, the wavelength in nanometers as would occur in a vacuum.
Channel
In WDM systems, each input channel is assigned a unique wavelength (i.e. color of light), thus the
channels can traverse the fiber "in parallel".
Pass Band
A pass band is the range of frequencies or wavelengths that can pass through a filter. It is one of the
parameters of WDM filters. In practice, it is the tolerance of the filter for laser drift away from the
center wavelength. For example, a typical pass band for CWDM filters is ± 6.5 nm about the center
wavelength. So a 1551nm laser could operate within a range of 1544.5 nm to 1557.5 nm without
encountering extra channel loss.
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Insertion Loss
Insertion loss is the attenuation caused by the insertion of WDM filter in an optical transmission
system. It is normally specified as the maximum insertion loss occurring across the filter pass band.
The insertion loss of a WDM product is given as the maximum insertion loss occurring at the
channel port with the highest loss. In WDM networks, insertion loss is one of several contributors to
the total loss of the communication link. Thin film filters exhibit fairly wide manufacturing variance
in their insertion loss values and are screened prior to use in WDM products.
Polarization Dependent Loss (PDL)
The loss exhibited by a WDM filter is dependent on the optical polarization of the light. PDL is the
largest difference in maximum insertion loss occurring at all states of optical polarization. PDL for a
WDM product is specified as the largest allowed PDL for any channel.
Polarization Mode Dispersion (PMD)
PMD is an important linear phenomenon occurring inside optical fibers, which can cause the optical
receiver to be unable to interpret the signal correctly, and results in high bit error rates. It is another
polarization effects that lead to impairments in the long-haul optical fiber transmission systems.
Return Loss
Return loss is the loss of power in the signal returned/reflected by a discontinuity in a transmission
line or optical fiber of WDM systems. A large value of return loss is desirable for preventing
problems with source lasers and reducing transmitted loss. Return loss for a WDM product is the
smallest, measured return loss at all ports.
Passband Ripple
Passband ripple is defined as the maximum peak-to-peak loss variation within the passband of one
channel.
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Isolation
Isolation is a measure of light at an undesired wavelength at any given point. Expressed in dB, it is
the difference of the maximum insertion loss within the filter pass band and the minimum loss
occurring within other filtering pass bands. Isolation is measured by applying a swept optical power
source to the filter's common port and measuring the loss within the filter's pass band and the pass
bands of other filters. When other filters are those with pass bands nearest to the filter's pass band,
it is called the Adjacent Channel Isolation. For the remaining ports, it is called the Non-Adjacent
Channel Isolation.
Operation Temperature
Operating Temperature (°C) is the ambient temperature range over which the device's performance
spec can be met.
Storage Temperature
Storage Temperature (°C) is the ambient temperature range over which the device can be stored
without affecting its intended application afterwards.
Water Peak
At 1385 nm, overtones of the OH- contamination-related molecular absorption manifest themselves
in the well known "water peak". Attenuation at and near the water peak can exceed 2 dB/km
compared with attenuation values of <0.2 dB/km as can occur in the C-band (1530 – 1565 nm).
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New Network Technologies Based on WDM
On the basic of WDM, some new network technologies have emerged, such as:
Wavelength Division Multiplexing-Passive Optical Network (WDM-PON)
WDM-PON is an innovative concept for access and backhaul networks. It uses WDM over a physical
P2MP fiber infrastructure that contains no active components (i.e., PON). WDM-PON allows
operators to deliver high bandwidth to multiple endpoints over long distances.
Optical Transport Network (OTN)
OTN was designed to provide support for optical networking using wavelength-division multiplexing
(WDM) unlike its predecessor SONET/SDH. It is able to provide functionality of transport,
multiplexing, switching, management, supervision and survivability of optical channels carrying
client signals.
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The knowledge is endless, thus, the word you see on this page as only the tip of an iceberg. But
once you know all of them, you may better know about WDM systems.
Warm Tips: Fiberstore offers a variety of WDM Mux/DeMux equipment that are in stock and can be
shipped in 12 hrs. Visit www.fs.com or contact us over sales@fs.com for more details.
Contact Us
Manufacturing R & D (China)
Eastern Side, Second Floor, Science &
Technology Park, No.6, Keyuan Road,
Nanshan District, Shenzhen 518057,
China
Tel: +86 (755) 8300 3611
Fax: +86 (755) 8326 9395
Email: sales@fs.com
APAC Office (Hong Kong)
1220 Tung Chun Commercial Centre,
438-444 Shanghai Street, Kowloon,
Hong Kong
Tel: +852 81763606
Fax: +852 81763606
Email: sales@fs.com
North America (United States)
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WA 98188,United States
Tel: +1-425-226-2035
Fax: +1-253-246-7881
Email: sales@fs.com
London Office (United Kingdom)
Third Floor 207 Regent Street, London,
W1B 3HH, United Kingdom
Tel: +44 2081441980
Notice: This document is for informational purposes only and does not set forth any warranty, expressed or
implied, concerning any equipment, equipment features, or service offered or to be offered by Fiberstore.
Fiberstore reserves the right to make changes to this document at any time, without notice, and assumes no
responsibility for its use. This information document describes features that may not be currently available.
Contact a Fiberstore sales team for information on feature and product availability.
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