Category Archives: CWDM Systems

Installation Guide to CWDM MUX/DEMUX System

CWDM MUX/DEMUX System Overview

Coarse Wavelength Division Multiplexing (CWDM) is a wavelength multiplexing technology for access networks. It is designed to increase fiber optic network capacity without adding additional fibers. The wavelengths of CWDM channels range from 1270nm to 1610nm with 20nm spacing, which allows the use of cost-effective lasers. CWDM MUX/DEMUX system is a passive, optical solution to increase the flexibility and capacity of existing fiber lines in high-speed networks. By adding more channels into available fibers, the CWDM MUX/DEMUX system enables greater versatility for data communications in ring, point-to-point, and multipoint topologies for both enterprise and metro applications.

CWDM MUX/DEMUX System Components

All CWDM system components are passive and require no power supplies. They consist of the rack mount chassis, a set of CWDM MUX/DEMUX and CWDM OADM (Optical Add/Drop Multiplexing) modules with color-coded ports. The CWDM MUX/DEMUX takes 4 or 8 different wavelength channels and multiplexes them onto one common fiber cable for transmission to the network. Then it demultiplexes the channels it receives from the network and sends each channel to a different device. Multiple modules may be chained through the expansion port on the four-channel modules. Thus it increases flexibility and enables growth for evolving networks.

The CWDM OADM module can add or drop CWDM channels into an existing backbone ring. It provides the ability to drop one CWDM channel from the network fiber, while allowing all other channels to continue pass to other nodes. Similarly, the drop/insert module removes an individual channel from the network fiber, however, it also provides the ability to add that same channel back onto the network fiber. The drop/insert module supports two paths (east and west) for dropping and adding, so that network viability is maintained in a ring topology, even if a break occurs in the ring.

CWDM MUX/DEMUX System Installation Guide

Step1: Mount the system chassis on the rack. The CWDM rack-mount chassis can be mounted in a standard 19-inch cabinet or rack. Make sure that you install the rack-mount chassis in the same rack or an adjacent rack to your system so that you can connect all the cables between your CWDM MUX/DEMUX modules and the CWDM SFP transceivers.


Step2: Install the CWDM MUX/DEMUX modules. First loose the captive screws on the blank of module panel and remove the panel. Then align the module with the slot of the chassis shelf and gently push the module into the slot. Finally, ensure that you line up the captive screws on the module with the screw holes on the shelf and tighten them up.


Step3: Install CWDM SFP transceivers. Since each channel has a specific wavelength, transceivers must comply with the right wavelengths. Each wavelength must not appear more than once in the system. Device pairs must carry transceivers with the same wavelength.

Step4: Install the CWDM MUX/DEMUX to the switch. After inserting the CWDM SFP transceiver into the switch, single-mode patch cables are used to connect the transceiver to the CWDM MUX/DEMUX module.


Step5: Connect the CWDM MUX/DEMUX pairs. In a CWDM MUX/DEMUX system, multiplexer and demultiplexer must work in pairs. Two strands of single-mode patch cables are needed in the duplex MUX/DEMUX module and one strand for the simplex one. Simply insert single-mode cables from your system equipment to the appropriate port on the CWDM MUX/DEMUX or OADM module.


CWDM MUX/DEMUX system is an attractive solution for carriers who need to upgrade their networks to accommodate current or future traffic needs while minimizing the use of valuable fiber strands. With CWDM technology, you can accommodate Ethernet and SONET on a single fiber that enables converged circuit/packet networks at high demand access sites. Besides, CWDM MUX/DEMUX can work seamlessly with transceivers to optimize link length, signal integrity and network cost, thus becoming a single rack-mount solution for enhanced design, power and space efficiency.

The Essential Mux/Demux Device in CWDM system

CWDM is short for coarse wavelength division multiplexing. CWDM technology is a method of combining multiple signals on laser beams at various wavelengths for transmission along a single fiber optic cable. CWDM system provides channels like 4, 8, 12 and 16 with the spacing of 20nm. The spectrum grid can remain from 1270nm to 1610nm when multiple wavelengths added to one fiber. It’s a cost effective choice for transporting large amounts of data traffic in telecoms or enterprise networks. Because CWDM can increase a fiber network capacity without deploying more fiber cables thus avoid fiber exhaust.

As mentioned above, CWDM is used to increase the amount of information that can be transmitted over a single fiber. Then the optical wavelength multiplexer (MUX) and the de-multiplexer (DEMUX) are indispensable components to deal with small numbers of wavelengths in this system.

What is CWDM Mux/Demux? The CWDM Mux/Demux is a device designed to allow multiple optical signals with different wavelengths to pass through a single optical fiber strand and split the multi-wavelength optical signals. For example, with a multiplexer at the beginning of the network, a typical 4 channel CWDM will be used to multiplex four different wavelengths onto one fiber. This means four different networks/systems can be transmitted over the same fiber simultaneously. At the opposite end of the network, a CWDM demultiplexer to demultiplex the wavelengths to allow them to be directed to the correct receivers. But usually CWDM Mux and Demux are integrated in an entirety. So the optical transmission is done by dual fibers where one fiber is transporting data from east to weat and vice-versa. With highly reliable passive optics certified for environmentally hardened applications, the CWDM Mux/Demux lets operators make full use of available fiber bandwidth in local loop and enterprise architectures. It’s a flexible, low cost solution that enables the expansion of existing fiber capacity.

CWDM Dux and Demux

The followings are the features of CWDM Mux/Demux:

  • Long distance coverage of multiple signals on a single fiber strand
  • Good flexibility and expansibility
  • Low end-to-end insertion loss
  • Extended operating temperature range suitable for remote office environments
  • High optical fiber transmission capacity
  • Simple to install, requires no configuration or maintenance
  • Passive CWDM optical Mux/Demux design
  • Low content delivery costs where dark fiber is available

Based on these features, CWDM Mux/Demux module can be applied in broad fields: enterprises and carriers with fiber optic infrastructure, transmitting additional applications with existing fiber cables, connecting buildings to CWDM campus ring, connecting field offices to cental office, ideal solution for metro-core, metro-access and enterprises.

Fiberstore supplies passive CWDM Mux/Demux with all channels except the common 4, 8, 16, 18 channel. All CWDM Mux/Demux modules suit Gigabit & 10G Ethernet, SDH/SONET, ATM, ESCON, Fibre Channel, FTTx and CATV, etc. And various optional port configurations are available such as Express Port, Monitor Port, 1310nm passband port and 1550nm port for these multiplexers according to your choice.