Tag Archives: CWDM Mux/Demux

Embedded CWDM Solution for Fiber Channel SAN Extension

CWDM, as an established optical transport technology, is universally employed in optical network for transmission distance extension and fiber exhaust reduction. This technology has evolved for years and now is available for Fiber Channel applications with the rate up to 4.25Gb/s. Moreover, when compared with traditional transmission approach via multiple fibers, embedded CWDM technology also makes economic sense while used in 4G Fiber Channels, and that’s what we are going to address in this article.

Fiber Channel Overview

The 4G Fiber Channel effectively improves storage area networks (SANs) performance by doubling speed and offering backward compatibility with 2G and 1G systems. With the proliferation of bandwidth-extensive applications, fiber capacity is on the edge of exhaustion. However, the demand for extremely high-capacity data transmissions began to soar. In this case, it is critical for IT technicians to enhance Fiber Channel SAN capacity without increasing costs.

Economical Fiber Channel Solution: Embedded CWDM Technology

CWDM technology expands fiber capacity by multiplexing optical light signals of different wavelength on a single optical fiber. In a CWDM network, components like CWDM Mux/Demux and CWDM transceivers are indispensable. With CWDM, IP data (Gigabit Ethernet or 10G Ethernet) and storage data (4G/2G/1G Fiber Channel) can be transported over a single fiber infrastructure, eliminating the need for complex protocol conversion.

Until now, standalone CWDM solutions are the commonly used methods to transport LAN connections and SAN connections simultaneously between main and recovery sites. Despite that it generates high equipment cost and reduces system reliability. In this case, embedded CWDM emerges as an ideal alternative for use in Fiber Channel applications. Embedded CWDM integrates CWDM optics (like CWDM SFP transceivers) directly into the Fiber Channel switch or Ethernet router, offering better reliability and simplicity. Thus instead of laying more fibers and equipment, users can extend system capacity only by adding new CWDM SFPs, which greatly reduces human labor and overall expenditure.

embedded CWDM solution with CWDM SFPs

Embedded CWDM for Distance Extension in 4G Fiber Channel

While used for SAN distance extension, CWDM functions to reduce the amount of required WAN fibers. Here we take the example of a SAN extension between a primary site and secondary site. With solution A, the implementation requires several WAN fibers to get the capacity required.

multiple fiber in SAN

As for solution B, CWDM is adopted to multiplex several signals onto a single fiber pair. CWDM SFPs are directly plugged into the ports from the Fiber Channel switch to generate signals of specific CWDM wavelength. The CWDM Mux combines wavelengths onto a fiber pair, while the CWDM Demux splits these wavelengths into several fiber on the receiver site. Thus the number of required WAN fibers is reduced by the number of wavelengths used.

embedded CWDM in SAN extension

Benefits of Embedded CWDM Solution

Embedded CWDM system is easier to operate, which requires no additional network management or training. It introduces more reliability, flexibility and simplicity due to fewer components involved in the system. And its advantages become more evident when it comes to cost: Embedded CWDM solution simply offers lower investment expenditure and operation cost, since it removes the need for adding new fibers and equipment, which can be cost-prohibitive. Even that CWDM SFPs and CWDM Mux/Demux should be involved in CWDM system, the overall cost is just a fraction of multiple fiber transmission.


CWDM solution allows IT managers to achieve network capacity expansion in a more cost-effective, simplified and flexible way. Besides, it also provides enhanced performance and reliability for current need and future growth. For more CWDM solutions and information, visit www.fs.com or contact us via sales@fs.com.

How to Build DWDM Network Over CWDM Network

Using CWDM MUX/DEMUX has been widely accepted as the most cost-effective and time-save method to increase the existing fiber optic network without adding optical fibers. However, a CWDM network can only support up to 18 different wavelengths. Is there any possibility to increase the capacity of the existing CWDM network? Hybrid CWDM and DWDM network is being introduced to combine the DWDM wavelengths with the existing CWDM wavelengths.

Combing DWDM With CWDM to Increase Network Capacity

As we know the CWDM wavelengths ranging from 1260nm-1625nm with space channel of 20nm actually cover all the range of DWDM wavelengths (ranging from 1470nm to 1625nm). However, DWDM wavelengths have much smaller channel spaces (0.4nm/0.8nm/1.6nm) and can provide larger bandwidth than that of the CWDM wavelengths. To combine DWDM with CWDM, the CWDM wavelengths that are near DWDM wavelengths can be used to transmit the DWDM wavelengths. However, not all these CWDM wavelengths are suggested. Generally, wavelengths of 1530nm and 1550nm are used to combine the CWDM and DWDM network together. Similarly, not all the DWDM wavelengths are suggested to be combined with CWDM network. The following picture shows DWDM wavelengths that are suggested to be combined with 1530nm and 1550nm.

CWDM DWDM hybrid wavelengths

How to connect CWDM With DWDM

To combine the DWDM wavelengths with CWDM wavelengths, both CWDM MUX/DEMUX and DWDM MUX/DEMUXs should be used. The following picture shows the connection methods for hybrid CWDM and DWDM. On both ends of the fiber link, a CWDM MUX/DEMUX and a DWDM MUX/DEMUX with corresponding wavelengths are deployed. Connect the line port of the DWDM MUX/DEMUX to the 1530nm/1550nm channel port of the CWDM MUX/DEMUX, the DWDM wavelengths can be added to the existing CWDM network.


Easier Operation and Cabling Solution for Hybrid CWDM and DWDM

In the CWDM and DWDM Hybrid network, the CWDM MUX/DEMUX and DWDM MUX/DEMUX play the most important roles. To offer better operation and cabling environment for these WDM MUX/DEMUX, FMU series products which are developed by FS.COM has been introduced. This series of products combines the MUX/DEMUX into half-U plug-in modules, and installed in 1U rack for better cable management and network operation as shown in the following picture.

FMU DWDM over CWDM solution

For CWDM and DWDM hybrid network, a FMU CWDM MUX/DEMUX and a DWDM half-U plug-in module can be installed together in a FMU 1U rack chassis. Thus, the two modules can be linked together easily. Meanwhile, with clear port identification, the management and operation of the fiber optic network would be easier.


The CWDM network can be added with DWDM wavelengths by the using of CWDM MUX/DEMUX and DWDM MUX/DEMUX which support corresponding wavelengths. The DWDM wavelengths that are 6.5nm around 1530nm and 1550nm are suggested to be used for CWDM and DWDM hybrid network. For better network operation and cabling, FMU series WDM solutions are suggested, which can provide easier and more flexible connections between CWDM MUX/DEMUX and DWDM MUX/DEMUX. Kindly contact sales@fs.com for more details about DWDM over CWDM solution, if you are interested.

Source: How to Achieve DWDM Over CWDM

1310nm, 1550nm, Expansion and Monitor Ports on CWDM MUX/DEMUX

CWDM technologies have been widely accepted low cost and fast solutions to increase capacity of the existing fiber optic network without adding new fibers. To add more beneficial to CWDM networks, CWDM MUX/DEMUX, which is used to multiplexing and demultiplexing optical signals, is being added with special ports like expansion port, monitor port, 1310nm port and 1550nm port. What’s the function of these special port? Do you really need them on your CWDM MUX/DEMUX? This post will offer details about these special ports for your references.

1310nm, monitor port and expansion port

Special 1310nm Port and 1550nm Port on CWDM MUX/DEMUX

CWDM utilizes usually wavelength range from 1270nm to 1610nm with a channel space of 20nm, which means the 1310nm and 1550nm are also the CWDM wavelengths. A full channel CWDM MUX/DEMUX can have 18 channels using 1310nm and 1550nm as channel ports. Actually, in most cases, 1310nm and 1550nm are used as channel port in CWDM MUX/DEMUX. They should be connected to the corresponding colored CWDM fiber optic transceiver, like CWDM 1310nm SFP and CWDM 1550nm SFP+.

As 1310nm and 1550nm are usually used for long distance transmission in normal fiber optic network. Most long distance fiber optic transceivers are designed to work over 1310nm and 1550nm. For example, 10G SFP+ LR transceiver is working over 1310nm and 10G SFP+ ZR is working over 1550nm. The Special 1310nm port and 1550nm port on CWDM MUX/DEMUX can be directly connected to these transceivers to expand the capacity of CWDM network. This is the main function of the 1310nm and 1550nm ports on CWDM MUX/DEMUX.


However, the special 1310nm and 155nm ports can affect the transmission of the wavelengths near it. The two port cannot be added freely. If you want to add 1310nm or 1550nm ports on your CWDM MUX/DEMUX, wavelengths which are 0-40 nm higher or lower than 1310 nm or 1550 nm cannot be added to the MUX. The following shows the ports that you can add on your CWDM MUX/DEMUX in different cases.

  • If you add 1310nm port, the following ports can be added: 1370nm, 1390nm, 1410nm, 1430nm, 1450nm, 1470nm, 1490nm, 1510nm, 1530nm, 1550nm, 1570nm, 1590nm, 1610nm
  • If you add 1550nm port, the following ports can be added: 1270nm, 1290nm, 1310nm, 1330nn, 1350nm, 1370nm, 1390nm, 1410nm, 1450nm, 1470nm, 1490nm
  • If you add both 1310nm port and 1550 port, the following ports can be added: 1270nm, 1290nm, 1310nm, 1350nm, 1510nm, 1530nm, 1550nm, 1570nm, 1590nm
Expansion Port on CWDM MUX/DEMUX

Although CWDM has 18 channels that can be used for transmission, in many cases, not all these channels are needed at one time or when the CWDM network deployed. But once you want to add more wavelengths to the existing CWDM network, the expansion port on CWDM MUX/DEMUX will play an important role, which can combine two individual CWDM MUX/DEMUXs with different wavelengths as one CWDM MUX/DEMUX.

CWDM MUX/DEMUX with expansion port

Here takes this 16-channel FS.COM FMU CWDM MUX/DEMUX as an example. There are two half-U plug-in CWDM MUX/DEMUXs deployed in a 1U rack. The module on the left side has an additional expansion ports. If you connect the expansion port with the line port on CWDM MUX/DEMUX on the right side. The two CWDM MUX/DEMUXs can work as one. This is the magic of the expansion port. If your network hasn’t used all the CWDM channel and you can to add more in the future, you can buy add an expansion port on your MUX/DEMUX or add the expansion port on the new CWDM MUX/DEMUX in the future.

Monitor Port on the CWDM MUX/DEMUX

Unlike the above mentioned three special ports which can increase the capacity of the CWDM network, the monitor port literally is used for monitoring the CWDM network. In many cases, the monitor port is necessary which can simplify turn-up operations of CWDM networks, and can be used for in-service monitoring of the CWDM signals by connecting an optical spectrum analyzer or a power meter.

4-channel CWDM with monitor port


The 1310nm port, 1550nm port and expansion port are designed to increase the capacity of CWDM network. The Monitoring port is added for better network management and operation. Except the 1550nm port, all these port can also be added on the DWDM Mux/DEMUX and play the same function. Kindly visit WDM page for full series of CWDM and DWDM solutions, if you are interested.

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 sales@fs.com 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