Category Archives: How To

How to Extend Transmission Distance in DWDM Network?

DWDM network has been widely accepted as the most cost-effective and feasible solution to increase the fiber optic network capacity over long distance. Except the bandwidth, the transmission distance is also an important factor during the deployment of DWDM network. This post is to introduce how to ensure and extend the transmission distance in DWDM network.DWDM MUX/DEMUX

Proper DWDM Fiber Optic Transceiver Is Essential

Generally, the fiber optic transmission distance is affected by the data rate, light loss, light source, etc. During the deployment, technicians usually need to select proper fiber optic transceivers to ensure the light source is strong enough to support the long transmission distances. For instance, 1G DWDM SFP modules provided by the market can usually support transmission distance up to 100km, while for 10G DWDM SFP+ modules this distance decrease to 80km. If the longer transmission distance is to achieve, proper fiber optic devices should be added in the DWDM network to ensure the transmission quality. The following part will take the examples of 10G DWDM network which uses DWDM SFP+ modules supporting transmission distance up to 80km on both ends of the fiber link. This 10G DWDM network will be required to support fiber optic links up to 40km, 80km, 120km and 200km separately.DWDM SFP+

Case Study One: 40km DWDM Network

In this first case, this 10G DWDM network is required to support 40km transmission distance. As we are using the 80km DWDM SFP+ modules, if there are no other locations deployed between the two ends of this network, generally no other devices are required to be installed between the two DWDM MUX/DEMUXs. The light source of 80km DWDM SFP+ modules can support 10G transmission over 40km.40km DWDM network

Case Study Two: 80km DWDM Network

If this DWDM network is required to support 80km transmission distance, we will still use the 80km DWDM SFP+ modules. The light source of these 80km DWDM SFP+ modules might not be able to support such long transmission distance, as their might have light loss during transmission. In this case, pre-amplifier (PA) is usually deployed before the receiver to improve the receiver sensitivity and extend signal transmission distance. Meanwhile, the dispersion compensation module (DCM) can be added in this link to handle the accumulated chromatic dispersion without dropping and regenerating the wavelengths on the link. The following diagram shows the deploying method of this 80km DWDM network.80km DWDM network

Case Study Three: 120km DWDM Network

It is known that the light power will decrease with the increasing of transmission distance. More fiber optic devices should be added in the 120km DWDM network to amplify the optical signal transmission from the 80km DWDM SFP+ modules. The following diagram shows how to deploy this 120km DWDM network. Except the above mentioned pre-amplifier and dispersion compensation module, a booster EDFA (BA) is suggested to deploy before at the beginning of the transmitting side to further ensure optical signal can achieve 120km.120km DWDM network

The above cases just simply illustrate the deployment of 40km, 80km and 120km 10G DWDM network that uses 80km DWDM SFP+ modules as light source. Related products in the above mentioned cases are listed in the following table. Please note that during the deployment of these long haul DWDM network, the light loss and compensation dispersion should be well calculated.

80km DWDM SFP+ DWDM MUX/DEMUX DWDM optical amplifier  Dispersion Compensation Module
DWDM SFP+ 80km DWDM MUX/DEMUX Optical Amplifier Dispersion Compensation Module
FS.COM Long Haul DWDM Solution

In fact, DWDM technologies and products can achieve transmission distance much longer than 120km, like 170km DWDM and 200km DWDM. If you are interested, kindly visit our Long Haul DWDM Network page where you can find specific details for complete DWDM network deployment solutions.

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.

Single-Fiber CWDM MUX/DEMUX

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

Conclusion

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.

Which Fiber Optic Wall Plate Do You Use?

With the expansion of fiber optic network, fiber optic cables are widely deployed in buildings and houses to be closer to end users. In many cases, fiber optic cables are installed in-wall. And fiber optic wall plates are used to provide easier and safer connection between the feed cables and the fiber patch cables that are linked to the target devices. Customers should select the right types of fiber optic wall plate to ensure the performance and connection of the fiber links.

Size and Design of Fiber Optic Wall Plate

Fiber optic wall plates have different sizes. But the most commonly used fiber optic wall plates are with a size of 86mm*86mm. The design (orientation) of the fiber optic wall plate also varies according to different applications. There are mainly three designs: straight, box and angled which are shown in the following pictures.

straight fiber wall plate
box fiber wall plate
angled fiber wall plate

The straight fiber optic wall plates are most commonly used one in many offices and buildings. They can provide architectural design for in-wall and recessed installations. The box type fiber optic wall plates are usually used in FTTH applications to provide easy connecting environments and safe places for fiber patch cable storage. The angled fiber optic wall plate has better performance to decrease the bend loss cause the fiber patch cable would have a smaller bend radius after connected to these wall plates (as shown in the following picture).

Fiber Adapter Type of Fiber Optic Wall Plate

Fiber optic wall plate uses the fiber adapter installed on itself to provide the connection and disconnection for fiber optic cables. Thus, the selection of fiber adapter type on the wall plate is essential. There are fiber optic wall plates which installed with SC, LC, FC, ST, etc. Both simplex and duplex adapters are also available in the market. The fiber type and polishing type of the fiber optic adapters should also be considered if you want to choose the right one for your application.

Port Counts of Fiber Optic Wall Plate

Except the above mentioned factors, the port count that a fiber optic wall plate can provide should also be considered. The port count of fiber optic wall plate with a size of 86mm*86mm is usually ranging from one to four. For most FTTH box type fiber optic wall plate there are usually two ports, one for feed fiber cable, and one for fiber patch cable that is connected to the target device, which is shown in the following picture.

Same-Day Shipping Fiber Optic Wall Plates

After considering the size, design, fiber adapter type and port count of the fiber optic wall plate, you will roughly know which fiber optic connector is suitable for your applications. The following picture shows part of the commonly used fiber optic wall plates which are available for same-day shipping.

SC Simplex Fiber Optic Wall Plate 2-port SC Fiber Optic Wall Plate 4-port SC Fiber Optic Wall Plate
Single Port SC Simplex Fiber Optic Wall Plate 2-Port SC Simplex  Fiber Optic Wall Plate 4-Port SC Simplex Fiber Optic Wall Plate
LC duplex fiber optic wall plate 2-port LC duplex Fiber Optic Wall Plate 4-port-lc-wall-plate
Single Port LC Duplex Fiber Optic Wall Plate 2-Port LC Duplex  Fiber Optic Wall Plate 4-Port LC Duplex Fiber Optic Wall Plate

Kindly contact sales@fs.com for more details about fiber optic wall plate, if you are interested.

Source: Fiber Optic Wall Plate Selection Guide

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.

DWDM over CWDM

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.

Conclusion

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.

CWDM SFP

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

Conclusion

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.