Category Archives: CWDM & DWDM Mux Demux

Dual-Fiber or Single-Fiber CWDM Mux Demux for Higher Capacity Need?

What would you do if your network capacity can not meet your requirement? Will you put more fibers or update your system? In fact, these two methods are not very recommendable. Why? As your fiber cabling infrastructure is limited for adding fibers and high cost is required for upgrading system, these two methods are unworkable or too expensive. Under this condition, using a pair of CWDM Mux Demux to build a CWDM system with higher capacity is highly recommended. The CWDM Mux Demux is regarded as a key component for a CWDM system, as shown below. It can be simply divided into two types, dual-fiber and single-fiber CWDM Mux Demux. To meet the higher capacity need of your system, this post will mainly introduce the basic knowledge of the dual-fiber and single-fiber CWDM Mux Demux and guide you find a suitable fiber optic Mux Demux for building your CWDM system.

CWDM system

Dual-Fiber CWDM Mux Demux

Dual-Fiber CWDM Mux Demux is a passive device multiplexing and demultiplexing the wavelengths for expanding network capacity, which must work in pairs for bidirectional transmission over dual fiber. It enables up to 18 channels for transmitting and receiving 18 kinds of signals, with the wavelengths from 1270 nm to 1610 nm. The CWDM transceiver inserted into the fiber optic Mux port should have the same wavelength as that of Mux port to finish the signal transmission. For instance, the two reliable 4 channel CWDM Mux Demux showed below use four wavelengths, 1510 nm, 1530 nm, 1550 nm and 1570 nm, their corresponding CWDM transceivers also features the same wavelengths.

Dual Fiber CWDM Mux Demux

When the connection above works, the left 4 channel dual-fiber CWDM Mux Demux uses 1510 nm, 1530 nm, 1550 nm and 1570 nm for transmitting 4 kinds of signals through the first fiber, while the right 4 channel dual-fiber CWDM Mux Demux features 1510 nm, 1530 nm, 1550 nm and 1570 nm for receiving the signals. On the other hand, the transmission from the right to left use the same wavelengths to carry another 4 signals through the second fiber, finally achieving the bidirectional signal transmission.

Single-Fiber CWDM Mux Demux

Single-fiber CWDM Mux Demux should be also used in pairs. One multiplexes the several signals, transmits them through a single fiber together, while another one at the opposite side of the fiber demultiplexes the integrated signals. Considering that the single-fiber CWDM Mux Demux transmitting and receiving the integrated signals through the same fiber, the wavelengths for RX and TX of the same port on the Single-fiber CWDM Mux Demux should be different. Hence, if the 4 channel single-fiber CWDM Mux Demux is used for CWDM system, 8 wavelengths are required, the twice time as that of the dual-fiber one.

Single Fiber CWDM Mux Demux

The working principle of single-fiber CWDM Mux Demux is more complicated, compared to the dual-fiber one. As shown in the figure above, the transmission from the left to right uses 1470 nm, 1510 nm, 1550 nm and 1590 nm to multiplex the signals, transmit them through the single fiber, and using the same four wavelengths to demultiplex the signals, while the opposite transmission carries signals with 1490 nm, 1530 nm, 1570 nm and 1610 nm over the same fiber. As for the wavelength of the transceiver, it should use the same wavelength as TX of the port on the CWDM Mux Demux. For example, when the port of a single-fiber CWDM Mux Demux has 1470 nm for TX and 1490 nm for RX, then a 1470nm CWDM transceiver should be inserted.

Dual-Fiber vs. Single-Fiber CWDM Mux Demux

We always consider whether an item is worth buying according to its performance and cost. In view of the performance, the single-fiber CWDM Mux Demux can carry signals through only one fiber supporting fast speed transmission and saving the fiber resource, while the dual-fiber one requires two fibers for transmission with a higher reliability. Besides, using single-fiber CWDM Mux Demux can be easier to install. In view of the cost, the single-fiber CWDM Mux Demux is much more expensive than the dual-fiber. And the simplex fiber cable also costs higher than duplex fiber cable. Thereby, the whole cost for building single-fiber CWDM system must be much more higher. Like the two sides of the same coin, both the dual-fiber and single-fiber CWDM Mux Demux have their own advantages and disadvantages. Which one you should choose just depends on your system needs and your budget for building the CWDM system.

How to Build A Single-Fiber CWDM Network

In most fiber optic network, dual-way transmission is necessary, which is usually achieved via duplex fiber cable. However, in some cases, simplex fiber cable can also support dual-way transmission like network that uses BiDi modules. For instance, if you used a pair of BiDi fiber optic transceivers with one using 1270nm for TX and 1310nm for RX, the other BiDi module should use the same but reversed wavelengths for TX and RX on the other end of the fiber link. Thus, a pair of dual-way signal can be transmitted on the same fiber via two different wavelengths. When it comes to build a single-fiber CWDM network, things will be a little different. However, the basic principle is similar, which is using different pairs of wavelengths to transmit different pairs of dual-way signal.


To build a CWDM network, CWDM MUX/DEMUX should be deployed on each end of the fiber optic link. There is also single-fiber CWDM MUX/DEMUX which is used to combine different wavelengths over the same fiber for dual-way transmission. Unlike dual-fiber CWDM MUX/DEMUX which uses the same wavelength for a pair of dual-way signal transmission, single-fiber CWDM MUX/DEMUX uses two different wavelengths for each pair of dual-way signal. A 4-channel dual-fiber CWDM MUX/DEMUX only uses four different wavelengths. However, a 4-channel single-fiber CWDM MUX/DEMUX will use eight different wavelengths which are divided into four pairs for dual-way transmission.

9-ch single-fiber CWDM
TX 1270nm 1310nm 1350nm 1390nm 1430nm 1470nm 1510nm 1550nm 1590nm
RX 1290nm 1330nm 1370nm 1410nm 1450nm 1490nm 1530nm 1570nm 1610nm

The above picture shows a 9-channel single-fiber CWDM MUX/DEMUX which uses 9 of the CWDM wavelengths for transmitting and the other 9 CWDM wavelengths for receiving. There are one simplex line port and 9 duplex channel ports loaded on the front panel. And each duplex channel port uses two different wavelengths which are clearly marked on the front panel. The following picture is also a 9-channel single-fiber CWDM MUX/DEMUX which is used together with the above one. However, the ports for TX and RX are all reversed to ensure the dual-way transmission.

9-ch single-fiber CWDM
RX 1290nm 1330nm 1370nm 1410nm 1450nm 1490nm 1530nm 1570nm 1610nm
TX 1270nm 1310nm 1350nm 1390nm 1430nm 1470nm 1510nm 1550nm 1590nm
CWDM Transceiver Selection for Single-Fiber CWDM MUX/DEMUX

To build a single-fiber CWDM network, CWDM fiber optic transceiver installed on devices like switches is usually connected to the channel port of CWDM MUX/DEMUX. However, as the channel port on the single-fiber CWDM MUX/DEMUX support two different wavelengths. The selection of CWDM fiber optic transceivers for this type of MUX/DEMUX might be confusing. Actually, it is quite simple. You just need to consider about the wavelength TX (transmitting) port. For instance, if one of the duplex port uses 1270nm for TX and the other use 1290nm for RX, then the a 1270nm CWDM transceiver should be used for this ports. While on the other end of this link, a 1290nm CWDM transceiver is required.

The following picture shows a 10G 4-channel single-fiber CWDM network which can better illustrate how to use single-fiber CWDM MUX/DEMUXs and how to select CWDM fiber optic transceivers for single-fiber CWDM MUX/DEMUX. Each wavelength just runs on one direction in single-fiber CWDM network.single-fiber CWDM network


Connecting the CWDM fiber optic transceivers installed on switches with the correspond channel ports on the single-fiber CWDM MUX/DEMUX and connect the line ports of the two CWDM MUX/DEMUXs via single-mode simplex fiber, a simple single-fiber CWDM network can be built. The above content just offers the basic concept of how a single-fiber CWDM network is like. There are actually a lot of factors to be considered during practical deployment, like light loss, transmission distance, and optical signal dropping and adding. IF you are interested, kindly visit FS.COM for more details.

How to Build 10G CWDM Network

As a passive technology, CWDM allows for any protocol to be transported over fiber optic link at specific wavelengths. CWDM technology is a cost-effective and simple method to increase the capacities of fiber optic network, by using different wavelengths to carry different signals over a single optical fiber. The wide deployment of CWDM network is greatly driven by its affordable cost.

What Is Need for A 10G CWDM Network?

The deployment of a 10G CWDM network is relaying on the exiting fiber optic network. Adding some components on the existing network can largely increase its capacity for data transmission. Here will introduce the key component and an important step during 10G CWDM network deployment.

CWDM Mux/Demux
A Key Component—CWDM Mux/Demux

A key component should be deployed is CWDM Mux/Demux, which combines different wavelength signals from different optical fibers into a single optical fiber, or separates different wavelength signals coming from a single optical fiber to separate optical fibers. The Channel number of a CWDM Mux/Demux is an important factor to divide this device. Standards have identified 18 CWDM Channels. Most of the CWDM Mux/Demux are provided with Channel number range from 2 to 16. However, FS.COM provides a 18-Channel CWDM Mux/Demux which can increase capacity of CWDM network to the most. CWDM Mux/Demuxs also come into a variety of package form factors. The most commonly used are LGX design, rack design and pigtail design.

CWDM Cabling
An Important Step—Connecting CWDM Mux/Demux With 10G Switch

Connecting CWDM Mux/Demux with a 10G switch, is the most important step to build a 10G CWDM network. In simple, to add more devices on the fiber optic network by CWDM technology is to connect the CWDM Mux/Demux with the 10G switches which are linked to the end users. To link CWDM Mux/Demux with the switches, fiber patch cable and 10G CWDM SFP+ transceiver are needed. 10G CWDM SFP+ transceiver should be installed on the switch SFP+ port (some switches use XFP port, then 10G CWDM XFP transceiver is required). Then a length of fiber patch cable should be used to link the transceiver and CWDM Mux/Demux.


How to Select to Right 10G CWDM SFP+ Transceivers?

Choose the Right Working Wavelength: To ensure the right connection, the specific wavelength port should be connected to the same wavelength CWDM SFP+ transceivers. For example, the port on the CWDM Mux/Demux marked with 1270 nm, should be connected to a CWDM SFP+ transceiver that working over wavelength of 1270 nm. As there are 18 different CWDM wavelengths, 10G CWDM SFP+ transceivers that are provided in the market also can 18 different versions for these wavelengths.

Choose the Compatible CWDM SFP+: It is common sense that the fiber optic transceiver should be compatible with the switch which it works on. For instance, if you are using a Cisco switch, the fiber optic transceivers that you used with this switch should be original Cisco transceivers or Cisco compatible transceivers which are provided by third party vendors. The latter is usually the choice of many companies, this is because third party transceivers are usually more cheap than the original brand transceivers. Fiber optic transceivers provided by third party vendor like FS.COM are all fully tested on original brand switch to ensure their compatibility and quality. What’s more, most of FS.COM fiber optic transceivers support same day shipping. Select the right SFP do not only cut your cost and time, but also provide high network performance.

Choose the Transmission Distance According to Your Needs: CWDM network is usually deployed for long distance transmission. Thus the 10G CWDM SFP+ transceiver that are provided in the market usually support transmission distance longer than 20 km, some can support link length up to 80 km or more. You can select the 10G CWDM SFP+ according to your requirements.

Here list the generic whole band 10G CWDM SFP+ fiber optic transceivers that support link length of 20km, 40km and 60km. If you need the brand compatible CWDM SFP+, kindly contact or visit FS.COM for more details.

Wavelength 20km CWDM SFP+ 40km CWDM SFP+ 60km CWDM SFP+
1270 nm 44170 44363 44743
1290 nm 44171 44364 44744
1310 nm 44172 44365 44745
1330 nm 44173 44366 44746
1350 nm 44269 44367 44747
1370 nm 44270 44368 44748
1390 nm 44271 44369 44749
1410 nm 44272 44370 44750
1430 nm 44273 44371 44751
1450 nm 44274 44372 44752
1470 nm 44299 44550 44827
1490 nm 44300 44551 44828
1510 nm 44301 44552 44829
1530 nm 44302 44553 44830
1550 nm 44303 44554 44831
1570 nm 44304 44555 44832
1590 nm 44305 44556 44833
1610 nm 44306 44557 44834

With the improvement of technology and market, the cost of CWDM network has decrease a lot. To build a 10G CWDM network is affordable to most companies. For full series of CWDM network Solutions, please visit the following link: WDM Solution

Using 40 CH DWDM MUX/DEMUX for 500G Network

WDM technologies are considered to be the most cost-effective solution to expand the existing network without adding additional fiber optic cable. The two types of WDM architectures—CWDM and DWDM have already been widely deployed in current network systems and can support 40G/100G network easily. DWDM has advantages over CWDM as it can multiplexing more wavelengths.

Does 40-Channel WDM MUX/DEMUX Stop at 400G?

For the traditional 40 CH DWDM MUX/DEMUX, each port is connected to a transceiver by a length of patch cable. Currently the most commonly used optics for DWDM are 10G SFP+ modules. Thus, for a 40 CH MUX/DEMUX, up to 400G can be reached by using forty 10G DWDM SFP+ modules. Is that the limitation of DWDM network? One of the most significant spirits of this industry is challenging the limit of data rate. Actually, with a small change on the DWDM MUX/DEMUX, the capacity of DWDM network can be largely increased and it doesn’t cost much. This post will take an example of the most commonly used DWDM MUX/DEMUX which has 40 channels (from C21 to C61) in a 1R rack. But the 40 CH DWDM MUX/DEMUX that we use is a little different from the traditional ones.

That’s the Beauty of 1310 nm

The difference laying at the front panel of the 40 CH DWDM MUX/DEMUX—a pair of 1310 nm port is added to the device. And this is the key point why we can move another step on forward the way to increase DWDM network capacity. The following picture show the logical setup of this 40 CH DWDM MUX/DEMUX.


The 1310nm port can be used for 40G/100G transceivers, like 40GBASE-LR4/ER4 or 100GBASE-LR4/ER4 transceivers. The 40G/100G signals can be multiplexed with the other 40*10G signals on the other 40 channels. Together with this pair of 1310 nm port, a 40 CH DWDM MUX/DEMUX can run up to 500G.

The beauty of this port is not limited to data rate increasing. It can also save a lot of money and spaces. You do not need to add another 10 ports and 10 pairs of SFP+ modules for additional 100G transmission. No change in the cabling infrastructure is required. Just a pair of 100G optics and a pair of patch cables, you can get another 100G service. The following picture shows the application of this 40 CH MUX/DEMUX with 1310nm port. (Click the picture to enlarge it.)

40CH DWDM solution

Cabling Solution for 40 CH DWDM MUX/DEMUX With 1310nm Port

Here offers the detailed cabling solution for this 40CH DWDM MUX/DEMUX with 1310nm port. Kindly contact for more details.

Item Number ID# FS Part Number Item Description
1 35887 40MDD-1RU-A1-FSDWDM 40 Ch 1RU Duplex DWDM MUX DEMUX C21 to C60 with 1310nm Port and Monitor Port
2 14491 DWDM-SFP10G-40 10GBASE 100GHz DWDM SFP+ 40km, LC Duplex Interface, C21 to C60
31533 DWDM-SFP10G-80 10GBASE 100GHz DWDM SFP+ 80km, LC Duplex Interface, C21 to C60
14599 DWDM-XFP10G-40 10GBASE 100GHz DWDM XFP 40km, LC Duplex Interface, C21 to C60
14650 DWDM-XFP10G-80 10GBASE 100GHz DWDM XFP 80km, LC Duplex Interface, C21 to C60
3 35208 QSFP-LR4-40G 40G QSFP+ LR4 1310nm 10km, LC Duplex Interface
35210 QSFP-ER4-40G 40G QSFP+ ER4 1310nm 40km, LC Duplex Interface
35014 CFP2-LR4-100G 100G CFP2 LR4 1310nm 10km, LC Duplex Interface

CWDM in hybrid access network in the use of the business

With the improvement of people’s living standard, nowadays a single network access gradually cannot satisfy people’s demand for network now, CWDM system support for the characteristics of business more and more get the attention of people, can also provide E, FE, GE, STM 1/4/16 SDH and ATM signaling, CATV video interface and other businesses such as access CWDM system solutions, to meet the requirements of people now.

Radio and television networks in recent business growth is faster in a given area, is the region development education network access project, due to the previous optical fiber network resources is mainly used in cable television network, optical fiber resources is not so rich, many county to the town had no residual fiber resources, to increase the data business, now want to be in the original on the fiber optic cable TV network transmission using again, plus information data signals, or want to lay out the other cable the main work, need to solve as many towns in this area belongs to mountainous area, cable laying is not very convenient, considering various factors such as resources, cost, on the radio and television networks company specialized in optical network access technology co., LTD. Shenzhen Fiberstore CWDM system to conduct a comprehensive performance analysis and product testing.And start in areas such as education network access to a project on each node USES many Fiberstore CWDM system equipment.


The radio and television networks of CWDM project at present is mainly used to implement the education network (10/100 MBPS Ethernet) hybrid transmission signals and the cable television network, the current direction of projects with a total of eight different contact, sharing the 3 sets of Fiberstore the CWDM system equipment.

In this scenario, A computer room – B node transfer 2 10/100 MBPS data signals and A cable TV signal, which is based on WDM CWDM access, two 10/100 MBPS signals after Fiberstore C5002S through Fiberstore HA – WDM multiplexer, and cable television signals and reuse all the way to A single fiber, transfer to the access point B region, middle transmission distance of 50 km, implements and Ethernet cable TV signal on the single fiber CWDM module of hybrid transmission.

A room – C nodes use sea pegatron C5002S system combined with high speed and CWDM terminal transceiver effectively cooperate with access, realize two-way 10/100 MBPS of hybrid transmission over A single optical fiber.
A-D-E by Fiberstore C5004S system combining various nodes of high speed and the corresponding CWDM transceiver implementation 4 10/100 MBPS signals on A single optical fiber access project, through the high speed connection between each contact, through the terminal CWDM wavelengths optical transceiver connected to A contact switch, after the C5004S system in the computer room 4 different signals, respectively in different wavelengths transmitted to each destination, after D primary school, through high speed download local signal, the remaining 3 to continue down the road signal to the corresponding destination.

Save fiber resources CWDM (Coarse where division multiplexing) Coarse wavelength division multiplexing system, which USES optical multiplexer in the different optical fiber transmission wavelength multiplexing in a single fiber transmission;On the receiving end of A link, using wavelength multiplexer and then revert to the original wavelength, using optical fiber all the way, on the whole link is solved effectively under the condition of the optical fiber resources extremely nervous network access, this scenario, A, D, E, between transmission on A single fiber and four 10/100 MBPS (also can be 1000 MBPS) signal, A room – B node is in the original cable TV signal transmission on A single fiber loading 2 10/100 MBPS signals, save A lot of fiber resources. 2.More business and high bandwidth CWDM is a according to the practical application to the transfer rate of adaptation based transmission platform, support a variety of business transfer.At each wavelength, the support of the business including 10 m / 100 m / 1000 m Ethernet, 155 m / 622 m / 2.5 G of SDH, 155 m / 622 m ATM business, as well as the Fiber Channel business, and so on.The whole system capacity to play a few Gbps data signal.Fully meet user bandwidth requirements in quite some time.This scenario USES is 10/100 MBPS business with cable TV signal for hybrid transmission.

CWDM system than the price of L band DWDM transceiver is relatively low, due to the power of CWDM is small, small volume, easy to use, thus supporting facilities, personnel training and the late maintenance cost is low.Compared with optical cable project: using CWDM device is opened rapidly, low cost, convenient network upgrades, late and increasing need of signal directly, or replace the higher rate of product, don’t need to change the fiber link, convenient network upgrades, reduces the network upgrade costs.The above scenario A-D-E, if change into 1000 MBPS data signals, the capacity of the network directly to upgrade to the 4 GBPS.
CWDM in hybrid access network in the use of the business.