Examples of CWDM Network Deployment Solution

Based on the same concept of using multiple wavelengths of light on a single fiber, CWDM and DWDM are two important technologies in fiber optical communications. As we all know, although the transmission distance of CWDM network is shorter than that of DWDM, it costs less and has the scalability to grow fiber capacity as needed. This article intends to give a simple introduction of components in CWDM networks and to explore some examples of CWDM network deployment cases.

Common Components Used in CWDM Networks

CWDM Mux/Demux

CWDM Mux/Demux, which is based on the film filter technology, is the basic component in CWDM networks. It can combine up to 4, 8 or 16 different wavelength signals from different fiber extenders to a single optical fiber, or it can separate the same wavelengths coming from a single CWDM source. That’s why CWDM can extend existing fiber capacity.

CWDM OADM (Optical Add-Drop Multiplexer)

A CWDM OADM is a device that can add (multiplex) and drop (demultiplex) channels on both directions in a CWDM network. It can add new access points anywhere in CWDM systems without impacting the remaining channels traversing the network. With this ability of OADM, the access points can be added to liner, bus, and ring networks, where the dual direction ring design provides redundant protected architecture.

CWDM Optical Transceiver

Optical transceiver is a necessary element in optical networks. And CWDM optical transceiver is a type of module supporting CWDM network application with CWDM wavelengths. When connected with CWDM Mux/Demux, CWDM transceiver can increase network capacity by allowing different data channels to use separate optical wavelengths (1270nm to 1610nm) on the same fiber. And the common CWDM transceiver type is SFP, SFP+, XFP, XENPAK, X2, etc.

CWDM Network Deployment Solution

Example One

Description: there are five buildings (Sheriff, Courthouse, Admin, Police & Fire, & Public Works) connected via multimode fiber cables (MMF) or single mode fiber cables (SMF). These buildings are linked via multimode SFPs in an existing D-link switches to create one network for internal use of the city offices. Below is a simple graph to show the situation.

Requirements: the goal is to install a single mode fiber network in town to connect numerous buildings. Some of these buildings have access to the city LAN. The Public Works building need to connect with Youth & Recreation Center, Library, Immanuel Lutheran School and the Senior Center. And all these buildings should have unfiltered Internet. Besides, the Waster Water Treatment Plant should be connected passing through the Senior Center. All these services are achieved using CWDM technology.

Solution: according to the requirements, this is a CWDM networks with several buildings to connect with. Here is the solution diagram.

In the diagram above, we can see there is an 8CH CWDM Mux/Demux connected with the switches. According to the requirements, Youth & Recreation Center, Library, Immanuel Lutheran School and Senior Citizen Center should be connected with the Public Works and need unfiltered services. Therefore, a 4CH CWDM OADM is placed after the CWDM Mux/Demux. Then the four wavelengths will be drop and into the four buildings. In addition, another CWDM OADM is deployed in Senior center to connect the Waster Water Treatment Plant, to meet the requirement. And each site also needs to use CWDM optical transceivers.

Example Two

Description: on site A, there are three Ethernet switches and a T3 router. And their working wavelengths 1470nm, 1490nm, 1510nm, 1530nm and 1610nm. Other three sites B, C, and D also have three Ethernet switches. And a T3 router is in site E. As the following figure shows.

Requirements: Considering the cost, all the wavelengths should be transmitted on a single fiber using CWDM technology.

Solution: according to the requirements, here is a simple diagram showing the solution.

In order to save cost, a 4CH CWDM Mux/Demux is used to multiplex four wavelengths (from three switches and one router) into one single fiber. At the first site B, a 1CH CWDM OADM is installed to remove one wavelength which is associated with network B. And other three sites are the same—dropping one wavelength associated with corresponding switch or router.

Summary

This article mainly introduces two CWDM network deployment examples. All the components like the CWDM Mux/Demux, CWDM OADM and CWDM transceiver are available in FS.COM. If you are interested in them, please contact us via sales@fs.com.

Related article:Differences between CWDM and DWDM

Sources:http://www.fiber-optic-components.com/examples-cwdm-network-deployment-solution.html

Things You Need to Know About OADM

As the quick development of telecommunications, people’s requirements for bandwidth continue growing. Optical network operators have to face great challenges to meet the demand. In this case, OADM appears. How much do you know about OADM? This article will introduce it for you.

OADM Overview

OADM, or optical add-drop multiplexer, is a passive optical device used in WDM technology. Its main function is to selectively separate or add optical signals or multiplex wavelength from one stream of light on a single fiber while other uncorrelated signals will not be affected. According to the wavelength, OADM has passive and active modes. In passive OADM, the add and drop wavelengths are fixed in advance, and it uses thin-film interference filters, fiber gratings, and planar waveguides in networks with WDM systems. Different from passive OADM, active OADM can be set to any wavelength after installation. And it is also more flexible and cheaper than passive OADM.

A traditional OADM consists of three stages: an optical demultiplexer, an optical multiplexer, and between them a method of re-configuring the paths between the demultiplexer, the multiplexer and a set of ports for adding and dropping signals. The demultiplexer separates wavelengths in an input fiber onto ports. The reconfiguration can be achieved by a fiber patch panel or by optical switches which direct the wavelengths to the multiplexer or to drop ports. The multiplexer multiplexes the wavelength channels that are to continue on from demultiplexer ports with those from the add ports, onto a single output fiber.

Types of OADM

Fixed optical add drop multiplexer (FOADM) and re-configurable optical add drop multiplexer (ROADM) are the two common types of OADM.

Fixed Optical Add-Drop Multiplexer (FOADM)

FOADM, sometimes also called configurable optical add drop multiplexers, can add or drop a fixed type or multiple fixed wavelength. In fixed-wavelength OADM, the wavelength has been selected and remains the same until human intervention changes it. FOADMs allow the manufacturers to customize the number of channels, filter specifications, and power equalization but require excessive transporters at each node. Although fixed optical add drop multiplexers lack of flexibility, they have more reliable performance and small delay.

Re-configurable Optical Add-Drop Multiplexer (ROADM)

ROADM is a device that can add, block, pass or redirect modulated infrared (IR) and visible light beams of various wavelengths in a fiber optic network. A laser tuned to a particular wavelength can electronically change the selected channel routing through the optical network. Hence, the ROADM provides flexibility for rerouting optical streams, and at the same time it can bypass wrong connections and allow minimal service disruptions.

Before ROADMs appear, signal routing in fiber optic networks was realized by converting the IR or visible beams to electrical signals and routing those signals using conventional electronic switches. The rerouted electrical signals were then converted back into IR or visible beams. Now with the application of ROADM, singles can be easily handled. Therefore, ROADM is widely used in systems that employ wavelength division multiplexing.

Application of OADM

As people’s requirements for bandwidth grow rapidly, network mangers not only need to satisfy this demand, but also face the challenge to keep track of all the wavelengths, monitor their correct operation and deploy new wavelengths easily without increasing the operation cost. However, the optical add-drop multiplexers which can couple two or more wavelengths into the same fiber add the required flexibility, and make it easy to add wavelengths or change the wavelength destination providing more convenient over the entire high capacity infrastructure. Therefore, optical add-drop multiplexer is widely used in long-haul optical communication system and metropolitan area network (MAN).

Besides, optical add-drop multiplexers play an important role in WDM networks. The typical applications are CWDM OADM and DWDM OADM. CWDM OADM is applied to optically add/drop one or multiple CWDM channels into one or two fibers. There are various CWDM OADM modules in our website such as 1CH CWDM OADM, 2CH CWDM OADM, 4CH CWDM OADM, 8CH CWDM OADM, 16CH CWDM OADM, etc. When numerous channels can be transmitted through a single fiber network, only selected channels of information are required at a particular place. At this moment, DWDM OADM can add or remove additional wavelengths in the network and make sure the signals spread correctly. There are 100 GHz and 200GHz DWDM OADM modules available for you.

Conclusion

In today’s world of intensive communication needs and requirements, OADM is a vital component in data networks. It plays a key role in improving the network performance and reliability. Now OADM is still progressing. Its great development prospect cannot be ignored.

Originally published at http://www.cwdm-dwdm-oadm.com/blog/a/76/Things-You-Need-to-Know-About-OADM