Fiber Optic Transceivers With CWDM Technology

CWDM (coarse wavelength division multiplexing) is the low-cost type of WDM technology, which is often used in metropolitan area network access networks. It is considered to be a flexible and economical solution to expand the existing network capacity without adding additional optical fibers. There are many devices deploying with CWDM technology used in telecommunication applications, like CWDM modules and CWDM Mux/Demux, to provide a cost-effective way for migrating to higher-rate infrastructures. This post will mainly introduce several fiber optic transceivers with CWDM technology.

Overview of CWDM Transceiver and Its Working Principle

CWDM transceiver is a hot-pluggable transceiver that combines with CWDM technology usually used to achieve connectivity between existing network equipment and CWDM Mux/Demux. This type of transceiver module can provide high-capacity bandwidth by carrying up to 16 channels on a single fiber in the spectrum grid from 1270 nm to 1610 nm with a 20 nm channel spacing, when used with CWDM Mux/Demux.

Similar to the working principle of prism, there is a multiplexer and a demultiplexer at the either end of the whole CWDM system. A multiplexer is at the transmitting end to combine several signals together, and a demultiplexer is at the receiving end to split the signals apart. The more detailed information can be see in the following image.

Several CWDM Transceiver Types

Actually, with the increasing need for CWDM technology in different applications, there are many types of fiber optic transceivers with CWDM technology, such as CWDM SFP, CWDM SFP+, CWDM XFP, CWDM X2, and CWDM XENPAK, etc. In the following part I will mainly introduce CWDM SFP, CWDM SFP+ and CWDM XFP.

CWDM SFP: CWDM SFP is hot-pluggable and transceiver component which is compliant with SFP MSA and IEEE 802.3 & ROHS. The transceiver uses a LC single-mode fiber to achieve data rates of 1G, 2G and 4G for the maximum link length of up to 200 km. You can connect the CWDM SFPs to CWDM passive optical system, add/drop multiplexer (OADM) modules or multiplexer and demultiplexer plug-in modules using single-mode fiber optic cables. Here is a Cisco CWDM-SFP-1270.

CWDM SFP+: CWDM SFP+ as shown below is based on the popular SFP form factor, which is an MSA standard build. It is designed for 10G Ethernet applications in data center, campus and metropolitan area access networks where require flexible and cost-effective systems. This type of CWDM module can reach a maximum speed of 11.25Gbps and is commonly used to support up to eight channels of 10G Ethernet over single-mode fiber at the wavelength including 1490 nm, 1510 nm, 1530 nm,1550 nm, 1570 nm, 1590 nm and 1610 nm.

CWDM XFP: CWDM XFP as shown in the image below, compatible with XFP MSA, is designed for single-mode fiber and operates at a nominal wavelength of CWDM technology, from 1270 nm to 1610 nm. CWDM XFP is mainly used for typical routers and switch line card applications.

Advantages of CWDM Transceiver

• Cost-saving—As we have mentioned above, CWDM module combining with CWDM technology can share a single fiber with several optical connections, thus expanding the bandwidth of fiber and allowing multiple applications to run over the same resources, which saves more cost than using other types of optical transceivers. Besides, due to the broader channel spacing in CWDM, cheaper uncooled lasers are used in CWDM modules, giving them another cost advantage.
• Increasing Network Capacity—By transmitting multiple data channels using separate optical wavelengths on the same optical fiber, CWDM modules can greatly increase network capacity. They reduce network equipment inventories, and eliminate the need to maintain extra units or devices with various fiber types for network repairs or upgrades. They can also enable the network to upgrade and to be in use over a longer time without replacing the whole network by providing interchangeable fiber connectors which can easily adapt to and modify any existing network.
• Low Power-consumption—Another advantage of CWDM module is low power-consumption. CWDM lasers without thermoelectric cooler and temperature control function, it is possible to significantly reduce the power consumption. For example a DWDM based module each laser is about 4 W power consumption, while the cooler CWDM module laser consumes only 0.5 W.

Summary

CWDM transceiver provides high speed and physical compactness that today’s networks require while delivering the deployment flexibility and inventory control that network administrators demand. FS.COM offers a wide range of CWDM modules, including the common used three types we have mentioned above, and the types we don’t discussed in detail, like CWDM X2, CWDM XENPAK, and CWDM GBIC. All of these modules are fully compatible with the original brand ones. You can come to FS.com for more detailed information.