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Understand Mux Ports On CWDM and DWDM Mux Demux

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Worton

Posted on December 20, 2016
December 4, 2020
2905

It is quite common to use CWDM or DWDM to increase the existing fiber optic network without adding any fibers. However, how much do you know about the mux ports on the CWDM and DWDM Mux Demux since there are a number of them? Get details about mux port explanation in the following text for better usage of CWDM and DWDM Mux Demux.

The Must-Have Ports on CWDM and DWDM Mux Demux

The basic function of the CWDM and DWDM Mux Demux is combining data rates of different wavelengths over the same fiber cable to increase the network capacity. Thus, channel ports supporting different wavelengths and Line ports used to connect the WDM Mux Demux are the must-have ports for these devices.

Channel Port

CWDM uses 18 wavelengths ranging from 1270nm to 1610nm with a channel space of 20 nm. Channel port count on CWDM Mux Demux is usually ranging from 2 to 18. A full-channel CWDM Mux Demux has all the 18 CWDM wavelengths: 1270 nm, 1290 nm, 1310 nm, 1330 nm, 1350 nm, 1370 nm, 1390 nm, 1410 nm, 1430 nm, 1450 nm, 1470 nm, 1490 nm, 1510 nm, 1530 nm, 1550 nm, 1570 nm, 1590 nm, 1610 nm.

DWDM uses the wavelength ranging from 1470 nm to 1625 nm usually with channel space of 0.8 nm (100 GHz) or 0.4 nm (50 GHz). DWDM Mux Demux can support much more wavelengths than CWDM Mux Demux. The channel port of a DWDM Mux Demux is usually ranging from 4 to 96.

Line Port

There are two types of line ports available for CWDM and DWDM Mux Demux. One is a dual fiber line port, and the other is a single fiber line port. The selection of the line port depends on applications. The WDM Mux Demux with a single fiber line port is very different from the WDM Mux Demux with a dual fiber line port on the use of wavelengths.

Dual-fiber Mux Demux uses the same wavelength for dual-way transmission, which means the TX port and RX port of every duplex channel port supporting the same wavelength. The WDM Mux Demux with dual fiber line ports installed on the two ends of the network could be the same.

For single-fiber WDM Mux Demux, all the wavelengths just flow in one direction. And the TX port and RX port of every duplex channel port supporting two different wavelengths. The above picture shows the front panel of an 8-channel DWDM Mux Demux with a single-fiber line port. As it is clearly marked the TX port and RX port use different wavelengths. If you choose a single-fiber WDM Mux Demux on one side of the network, there should be a single-fiber WDM Mux Demux that supports the same wavelengths but has the reverse order on the TX port and RX port of every duplex channel port.

Please note, the line port of some single-fiber CWDM Mux Demux is made into a duplex port, but only one port is functional. Here takes the example of FS FMU CWDM Mux Demux as an example, as shown in the following picture, the single-fiber CWDM Mux Demux has a duplex port, but one of the ports marked as "N/A" is not in use.

The Functioning Ports on CWDM and DWDM Mux Demux

Except for the above mentioned must-have channel ports and line port, WDM Mux Demux can also be added with other ports that bring more profits to the existing WDM network. The following will introduce these special ports that are often added on CWDM and DWDM Mux Demux.

Expansion Port

Expansion port added on WDM Mux Demux is really useful. If you installed a CWDM network which just uses several of the CWDM wavelengths, you can use this expansion port to increase the network capacity by connecting the expansion port with the line port of another CWDM Mux Demux supporting different wavelengths. Then the network of this CWDM network can be increased easily.

1310nm Port and 1550nm Port

The 1310 nm and 1550 nm are actually WDM wavelengths. How could these two wavelengths become special? It can be recognized that many fiber optic signals are transmitted over 1310 nm and 1550 nm. Many fiber optic transceivers supporting long distances use these two wavelengths. However, the standard channel port on WDM Mux Demux can only be connected to color-coded fiber optic transceivers like CWDM SFP/SFP+ and DWDM SFP/SFP+. With these specially designed 1310nm port and 1550nm port, the signal running through ordinary fiber optic transceivers can be combined together with other CWDM wavelengths.

Please note that DWDM Mux Demux can only add a special 1310nm port. For CWDM Mux Demux, not all the wavelengths can be added. There is a simple rule for how to add the special ports and other standard channel ports on CWDM Mux Demux. The following table shows the specific details.

If Add Special Port Other Channel-Port Can be Added
1310nm port 1390 nm, 1410 nm, 1430 nm, 1450 nm, 1470 nm, 1490 nm, 1510 nm, 1530 nm, 1550 nm, 1570 nm, 1590 nm, 1610 nm
1550nm port 1270 nm, 1290 nm, 1310 nm, 1330 nn, 1350 nm, 1370 nm, 1390 nm, 1410 nm, 1430 nm, 1450 nm, 1470 nm, 1490 nm
1310nm port and 1550 port 1390 nm, 1410 nm, 1430 nm, 1450 nm, 1470 nm, 1490 nm

Monitor Port

Many technicians will add a monitor port on CWDM or DWDM Mux Demux (see figure 2) for better network monitoring and management. If you choose a single-fiber WDM Mux Demux, the monitor port should be a simplex fiber optic port. For dual-fiber WDM Mux Demux, you can add a duplex monitor port for the whole network monitoring, or just add a simplex port for Mux or Demux monitoring.

Summary on CWDM and DWDM Mux Ports

From all the above, there are five main types of mux ports on CWDM and DWDM Mux Demux, including two must-have mux ports and three functioning ports. All the mux ports mentioned above are the most commonly used in WDM Mux Demux and each of them has its special function or usage. Some of these mux ports could be customized due to different suppliers to support more complete solutions for CWDM, DWDM and even DWDM over CWDM networks.