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Things You Should Know About CWDM Mux Demux and DWDM Mux Demux



This article will introduce the most essential component of the C/DWDM Mux Demux, the Mux port, and you will learn to build a higher capacity C/DWDM network by using the Mux port.

Among the C/DWDM devices, fiber optic Mux Demux is the most widely used device, and higher capacity C/DWDM networks can be built using fiber Mux Demux. Being an important component of CWDM and DWDM Mux Demux, ports are available in many different types to cope with various usage scenarios. Using ports can increase the capacity of an existing optical fiber network with no additional fiber. This article will introduce the mux ports on CWDM Mux Demux, such as the common Line port, Channel Port, Monitor Port, etc. This post will submit the different applications of these ports on CWDM Mux Demux. You will know more about C/DWDM Mux Demux through the introduction of this article.


Essential Ports on CWDM/DWDM Mux Demux


It is well known that the essential feature of C/DWDM Mux Demux is to increase the capacity of the network by grouping different wavelengths of data rates on the common fiber optic cable in this way. So the necessary ports on the C/DWDM Mux contain line ports connecting the external fiber to the fiber Mux Demux, and channel ports, which are dedicated to multiplexing and demultiplexing different wavelengths. The next section describes these two ports, the channel port, and line port.


Line Port


Line port has another name called common port. The line port is used for every C/DWDM channel multiplexing and demultiplexing, and is an indispensable port on CWDM/DWDM Mux Demux. Line port is generally divided into two different types: dual fiber and single fiber, and the corresponding type of port is generally selected according to the wavelength of WDM. The TX port and RX port of each duplex channel port work under the same wavelength. However, the TX port and RX port on a single-fiber WDM Mux Demux can support two different wavelengths, and all wavelengths will flow in the same direction


Figure 1:  Dual Fiber Line Port VS. Single Fiber Line Port


The image above shows how a single fiber line port differs from a dual fiber line port in an 8-channel DWDM Mux Demux. In some cases, the line port of a single-fiber WDM Mux Demux will also be available as a duplex port, however, the interface of this is the only one that can be used. As you can see in the third part of the picture above, although this CWDM Mux Demux is a single fiber, it still has a duplex line port, but the interface marked as "N/A" is in an unused state.


Channel Port


The channel port is likewise a mandatory port that can be used to transmit and receive signals on a particular WDM wavelength. As we know, CWDM technology utilizes 18 wavelengths, which range from 1270nm to 1610nm, with a 20nm interval wavelength in the middle of each channel. The number of channel ports on CWDM Mux Demux generally ranges from 2 to 18 channels. The DWDM technology uses wavelengths in the range of 1470nm to 1625nm, which generally has a channel space of 0.8 nm (100GHz) or 0.4nm (50GHz). Comparing these two technologies, DWDM Mux and Demux enable more wavelengths to be supported, and their channel ports range are generally from 4 to 96, and more signals can be multiplexed, using DWDM Mux Demux can realize a larger communication capacity.


Function Ports on CWDM/DWDM Mux Demux


There are some other function ports on WDM Fiber Mux Demux besides the channel port and line port. These ports are not as essential as these two previous ones, but they can bring some other benefits to the WDM network. The following section will introduce these common function ports that can be added to the C/DWDM Mux Demux.


Expansion Port


The expansion port allows WDM Fiber Mux Demux to increase the mounts of more wavelengths and channels to an existing WDM network. For example, if there are only 4 CWDM wavelengths in a previously installed CWDM network, by using the expansion port, the expansion port can be connected to another line port supporting a different wavelength of CWDM Mux/Demux, resulting in a larger network capacity. The current WDM fiber Mux Demux uses expansion ports to increase the existing network capacity, the following figure shows how to increase the network capacity by expansion ports.


Figure 2: How expansion port increase the network capacity


Monitor Port


The function of the monitor port is to monitor and manage the network. Most engineers today add a monitoring port to CWDM/DWDM Mux Demux, through which they can monitor and manage the network more easily. Using the monitor port allows WDM fiber Mux Demux to measure the signal's dB level while being able to ensure uninterrupted service. On a single fiber WDM Mux Demux, it should be paired with a simplex fiber port, and similarly, on a dual fiber WDM Mux Demux, it should be paired with a corresponding duplex monitoring port for the entire network monitoring activity. If you use simplex monitoring ports on a dual fiber WDM Mux Demux, you can also monitor Mux or Demux. These two switches use DWDM C51 wavelengths for signaling between them, while an optical power meter is used to monitor the fiber power between the two sites.


Figure 3: Monitor Port


1310nm Port and 1550nm Port


1310nm and 1550nm are the two common WDM wavelengths. Why are these two wavelengths typically used? We know that the channel ports on WDM fiber Mux Demux allow only color-coded optical fiber transceivers such as C/DWDM SFP+ to be connected. 1310/1550nm ports feature a special configuration that allows them to combine signals from 1310/1550nm transmitted by regular fiber transceivers with signals from other C/DWDM wavelengths. The following picture shows how a 500Gbps network connection can be achieved over an existing 40-channel DWDM fiber link using a 1310nm port.


Figure 4: 1310nm Port and 1510nm Port


In the architecture of this fiber link, a 100G fiber transceiver operating at 1310nm is first inserted into the end device. A section of optical fiber cable is then used to connect the existing DWDM network to the 1310nm port on the DWDM Mux Demux. The 1310 ports on both sides form a total 40x10Gbps DWDM network, which, together with the 100Gbps of the previous 1310 ports, constitutes a 500Gbps network architecture. 


In general, DWDM Mux Demux can only be added with special 1310nm ports, not all CWDM wavelengths, if you need to add other standard channel ports, you should follow the rules in the following table


Special Port Corresponding ports
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 & 1550nm port 1390 nm, 1410 nm, 1430 nm, 1450 nm, 1470 nm, 1490 nm





This article describes the five common C/DWDM Mux Demux ports. Each of them has a different purpose, and the corresponding port should be used in different situations. If you want to use C/DWDM Mux Demux properly and build a C/DWDM network using them. You should be able to have enough knowledge about these ports. If you have any questions about these ports, you can consult QSFPTEK.COM via sales@qsfptek.com. QSFPTEK can provide you with professional service, including C/DWDM network solutions, and various C/DWDM devices and related products.



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