CWDM & DWDM Mux/Demux Overview

As we all know, WDM (wavelength-division multiplexing) is a method of multiplexing a number of optical carrier signals onto a single optical fiber by using different wavelengths (colors) of laser light. It enables bidirectional communications over one strand of fiber, as well as multiplication of capacity. In a WDM system, a multiplexer (Mux) is used at the transmitter to join the several signals together, and a demultiplexer (Demux) is used at the receiver to split the signals apart. This article will focus on the CWDM & DWDM Mux/Demux.

CWDM Mux/Demux

CWDM (coarse wavelength division multiplexing) is an excellent choice for increasing bandwidth capacity while keeping costs down in short-range communication networks. CWDM Mux/Demux modules are bidirectional passive optical multiplexers and demultiplexers, allowing multiple optical signals at different wavelengths to pass through a single optical fiber strand. It can combine up to 18 different wavelength signals from different optical fibers into a single optical fiber, or separates up to 18 different wavelength signals coming from a single optical fiber to 18 separate optical fibers. The following picture shows the front panel of 18 channels 1270-1610nm dual fiber CWDM Mux Demux with monitor port.

18 channels 1270-1610nm dual fiber CWDM Mux Demux

18 channels 1270-1610nm dual fiber CWDM Mux Demux

DWDM Mux/Demux

DWDM (dense wavelength division multiplexing) solution is the preferred option for long-haul transmission. The DWDM Mux/Demux modules deliver the benefits of DWDM technology in a fully passive solution. Usually, they are used for long-distance transmission where wavelengths are packed tightly together over the C-band range of wavelengths, up to 48 wavelengths in 100GHz grid (0.8nm) and 96 wavelengths in 50GHz grid (0.4nm). Currently, the most common configuration of DWDM Mux/Demux is from 8 channels to 96 channels. The following picture shows the front panel of 40 channels C21-C60 dual fiber DWDM Mux Demux with monitor port and 1310nm port, which is ideally suited for high-density add/drop requirements in DWDM networks.

40 channels C21-C60 dual fiber DWDM Mux Demux

40 channels C21-C60 dual fiber DWDM Mux Demux

Comparison Between CWDM and DWDM System

Price difference—CWDM system carries less data, but the cabling used to run is less expensive and less complex. A DWDM system has much denser cabling and can carry a significantly larger amount of data, but it can be cost prohibitive, especially where there is a need for a large amount of cabling in an application.

Transmission distance—DWDM system is designed for longer distance transmission as stated above. They can transmit more data over a significantly larger run of cable with less interference than a comparable CWDM system. If there is a need for transmitting the data over a long range, DWDM system will likely be the best in terms of functionality of the data transmittal and the lessened interference over the longer distances that the wavelengths must travel.

CWDM system cannot transmit over long distances because the wavelengths are not amplified, and therefore CWDM is limited in its functionality over longer distances. Typically, CWDM can travel anywhere up to about 100 miles (160 km), while an amplified DWDM system can go much further as the signal strength is boosted periodically throughout the run. As a result of the additional cost required to provide signal amplification, the CWDM solution is best for short runs that do not have mission critical data.

FS.COM CWDM & DWDM Mux/Demux Solution

Multiplexing enables a high density, scalable fiber solution. It allows an increase in the fiber utilization by carrying multiple signals down an individual fiber connection, rather than investing in more fibers. As a professional manufacturer and supplier in telecommunication industry, FS.COM offers a full range of CWDM & DWDM Mux/Demux. Our Mux/Demux modules are designed for the best possible performance levels, which helps to expand the bandwidth of optical communication networks with lower loss and greater distance capacities. They are protocol transparent and perfectly suit various applications, such as PDH, SDH/SONET, Fibre Channel, etc. With different housing options, the end users can easily add CWDM or DWDM capabilities to their existing or new networks. For more details, please visit