A Brief Introduction to Multiplexing Technology in Optical Transmission Network

In optical transmission network, multiplexing technology is considered as an effective means to expand the transmission capacity of existing optical fiber networks. It can increase the transmission capacity of optic fiber in the most cost saving way, so as to quickly meet the increasing demand for high bandwidth. Now, some multiplexing technologies have been widely used and mature in optical transmission networks. In addition, there are some new multiplexing technologies that have been highly praised. In this tutorial, Gigalight will introduce two kinds of multiplexing technologies - wavelength division multiplexing (WDM) and optical time division multiplexing (OTDM), and a new kind of emerging technology - space division multiplexing (SDM).

The Multiplexing Technologies Being Applied

In modern optical transmission networks, wavelength division multiplexing (WDM) and optical time division multiplexing (OTDM) are two mainstream multiplexing technologies, which will be respectively described in detail in this section.

Wavelength Division Multiplexing(WDM)Tech

Wavelength division multiplexing (WDM) is a technology that uses a multiplexer (MUX) to multiplex optical carrier signals with different WDM wavelengths into one optic fiber on the transmitting terminal, and then using demultiplexer(DEMUX)to separate WDM wavelengths on the receiving end. Each WDM wavelength signal is independent from each other and is free from the effects of any transmission protocol and rate.Besides, wavelength division multiplexing (WDM) technology can also achieve bidirectional transmission of optical signals on one optic fiber. This tech virtulizes one optic fiber into multiple fibers. It does not only simplify the structure of the optical transmission network, but also greatly saves the optical fiber resources, so as to reduce the cost of optical network deployment. According to the difference of wavelength, wavelength division multiplexing (WDM) technology can be subdivided into coarse wavelength division multiplexing (CWDM) and dense wavelength division multiplexing (DWDM), which are different in wavelength interval, wavelength number and so on. Thereinto, CWDM (coarse wavelength division multiplexing) is generally used to cover a small area of LAN applications, while dense wavelength division multiplexing (DWDM) technology is used to cover a small range of metropolitan area network applications. The deployment cost of dense wavelength division multiplexing (DWDM) system is much higher than that of coarse wavelength division multiplexing (CWDM) system.

 

Optical Time Division Multiplexing (OTDM) Tech

Optical time division multiplexing (OTDM) is a time division multiplexing and demultiplexing in the optical field. It converts optical signals in each branch into high rate and ultra narrow short pulse signals, and then interplugged into allocated time slot in the multiplexed channel, thus realizing the purpose of high-rate transmission. It is an effective way to overcome the bottleneck of electronic circuit bandwidth and to make full use of the capacity-expansion scheme of low-loss bandwidth. However, its technology is not mature at present.

The mixed system composed of wavelength division multiplexing (WDM) and optical time division multiplexing (OTDM) technology can take advantage of each other's advantages in the tech. It is with these advantages such as high utilization rate of optical fiber bandwidth, large system transmission capacity, simple construction technology, reasonable price performance ratio and so on. It is the most efficient way to solve multi-user communication network about the high speed and large capacity transmission of the trunk line.

The Emerging Multiplexing Tech

Space division multiplexing (SDM) is a technology that simultaneously transmits different data streams by building parallel space channels in space dimensions, generally used in multiple input and multiple output (MIMO) systems. Currently, space division multiplexing (SDM) is considered as an effective way to solve the bottleneck of current metropolitan network bandwidth. It can greatly reduce the communication cost and energy consumption at the same time of increasing the bandwidth of the MAN.

In the above mentioned multiplexing techs, WDM is the most widely-applied, and its solution is very mature. Gigalight, as the optical interconnection design innovator, can provide solutions about WDM tech, such as QSFP28 CWDM4, QSFP28 4WDM-20 and other DWDM series optical module. If wanting to know more details, you can visit at Gigalight official website.

The Reasons Why Optical Transceiver Is in Failure?

In order to ensure that the optical module can work normally, it is very important to check optics to avoid the failure of optical modules. When it comes to the reasons why optical transceiver is in failure, there are still many people confused of it. Then there will be an annalysis on it by Gigalight for you.

1. The Reasons Why Optical Module Is in Failure?

The failure of optical transceiver module usually means the failure of receiving terminal and transmitting terminal. The factors that cause the failure of optics include the following aspects:

• Optical Interface Is Polluted and Damaged

The pollution and loss of optical transceiver module will lead to that the dissipation of optical link becomes bigger so that the optical link is unlocked. However, what are the reasons to cause this problem? Threre are these factors as below:

The exposure of the opticla interface for a long time causes the dust into the interface so as to bring about the pollution; the surface of the used optical module is polluted, leading to the secondary pollution of the optical module's optical interface;the endface of the optical connector with tail fiber is scratched; the quality of the optical module is too poor.

• ESD Damage

ESD means electrostatic discharge. ESD can produce a lot of static electricity, which will adsorb dust and change the impedance between lines. Simultaneuosly, the heat generated by the instantaneous current of ESD can cause the component to be damaged, or even completely damaged. The causes of ESD damage are as follows:

The environment is too dry; there is irregular operation, such as non hot pluggable optical module operating under electrification, without anti-static packaging in the process of transportation and storage; the equipment is without ground connection or imperfect earth.

2. The Procedures to Check the Failure of Optical Module

If the situation of no optic or low optical power rate happens, these measures can be taken:

Cleaning the interface of optical module; checking whether there are scratches and bending on the optic fiber connector; checking the wavelength of the optical power and the measurement unit(dBm); the hot pluggable module can restart a plug test;test on the same ports by changing modules or on the same optical modules by changing the ports.

3. How to Avoid the Failure of Optical Module?

• The Prevention Measures for Optical Interface Pollution of Optical Module:

Before operating the optical module, the paper for wiping optic fiebr must be prepared well. The optical port must be cleaned before the patch cord is inserted into it to avoid the secondary pollution of the port caused by the endface pollution of patch cord. On account that a piece of paper can only wipe one place, it is necessary to prepare at least 3 pieces of paper; the specific way is to wipe the fiber head horizontally in one direction; the temporaryly-unused optical module must be worn a dust cap to avoid dust pollution; If no dust cap is available, it can be replaced by the optic fiber; if the optical module or optic fiber has not been used for a long time, the optical interface and optic fiber must be cleaned before they are utilized. Besides, what should be paid attention is that cleaning optical port needs to use cotton stick, and cleaning optic fiber port needs to use paper for wiping optic fiber. And at the process of cleaning, pls insert cotton stick into the optical port, gently rotating, not excessive force.

• The Prevention Measures to Avoid Optics Burnout

When using the OTDR table to test the link degree or attenuation degree of the optical fiber channel, the optic fiber can not disconnect with the optical fiber. Otherwise, the optical module is easily burnt down.

4. Conclusion

All in all, keeping the optical interface clean and avoiding interface polluted are essestial to aviod the failure of optics. Above is the shared information for optical transceiver. Hoping it can be helpful to you in future application of optical transceiver. More information about it are at Gigalight.

About Gigalight:

Gigalight is a design innovator in global optical interconnect field. A series of optical interconnect products include: optical transceivers, passive optical components, active optical cables, GIGAC MTP/MPO cablings, cloud programmers & checkers, and etc. Three applications are mainly covered: Data Center & Cloud Computing, MAN & Broadcast Video, and Mobile Network & 5G Optical Transmission. Gigalight takes advantage of its exclusive design to provide clients with one-stop optical network devices and cost-effective products.

What Are the Impacts of High or Low Temperature on Optical transceivers？

It is known that temperature plays a key part in the working process of optical transceiver. Whether it is too high or low will have an impact on the optical module. Then what are the impacts of too high or low temperature on optical transceiver module on earth? In this post, Gigalight will have an introduction to it.

What Is the Normal Temparature of Optical Transceiver?

Due to various types and brands of optical module, different optics temperature level corresponding to the different temperature range and varied temperature range defined by suppliers, whether the temperature of optical module is irregular can be judged accoerding to these factors. Before using optical transceiver, it is the best to check the brand or suppliers' definition to the temperature range of optics, so as to reduce series of problems caused by irregular temperature of optical transceiver.

Besides, with respect to the temperature of optics, it consists of commercial grade, extended grade, industrial grade(shown as the below):

Temperature Grade	Abbreviation	Temperature Range
Commercial temperature range	COM	0 ~ + 70 ℃
Extended temperature range	EXT	-20 ~ 85 ℃
Industrial temperature range	IND	-40 ~ 85 ℃

The Reasons Why the Temperature Are too High or too Low

1. The Poor Quality and Workmanship

If you use the optical transceivers with poor quality and workmanship, then the phenomenon of irregular temperature of the optical transceivers is more common. Because the function of such optical transceivers is instable, heat dissipation is also relatively poor. In order to reduce the temperature anomaly and unnecessary discard, we advise to use the optical transceivers with better function, quality and workmanship.

2. Poor Application Conditions

The working conditions of optics is in data center, computer room or on the switcher. If it is applied in the other conditions, the change of environment temperature will definitely change that of optical transceiver module. Furtherly, the optical power and optical sensitivity of optics will be affected. If the application conditions of optical transceiver is relatively poor, the optical transceiver module with industrial temperature and extended temperature will be recommended.

3. The Appliction of Used Optical Transceiver

The temperature range of brand new optical module is usually at 0-70℃, and many used optics can not reach that. Therefore, under the conditions of too high and too low temperature, used optical module is unable to work normmally. At this time, the brand new optical module is suggested.

What Are the Impacts of Too High or Low Temperature on Optical transceivers？

1. The Impact of Too High Temperature on Optics:

If the working temperature of optical module is too high, its optical power will become larger. After that, the error will happen in the process of receiving signal and even optical module is burnt out, causing that the optical module can not work normally. At this time, the DDM function should be increased, or a temperature control system should be used to monitor and compensate it in real time, so as to ensure optical module's extinction ratio and optical power are stable and the normal working of optical communication system.

2. The Impact of Low Temperature on Optics

Generally speaking, as long as the optical transceiver is not exposed to the temperature below 0℃ and the temperature is not too low, it is not suggested to use optical transceiver under the conditions of too low temperature, which will lead to the instability of optical module.

Conclusion

Above is about the introduction to the impacts of too high or too low temperature on optical transceiver module. Hoping it will be beneficial to your future application of optical transceiver. More information about it at Gigalight.

The Development Direction of Optical Transceiver

Optical transceiver is widely applied in the communication network. To some degree, users’ more demands on optical communication network promotes the development of optical transceiver module. Nowadays' communication network is developed toward higher information transmission rate, smaller in volume of communication devices. Then how about the development direction of optical transceiver? In this article, Gigalight will have an introduction to it.

The Development Direction of Optical Transceiver

1. Faster-Higher Transmission Rate

People demand more for the amount of information transmission, and require higher rate of information transmission. The rate of optical module is developd from the Mbit, Gigabit to 40G, 100G and even more.

2. Smaller-Miniacturization

In the gradually-rapid competition of optical communication market, the volume of communication device is also smaller. To meet the requirements of optical communication device, optical transceiver is gradually developed into the highly-integrated package. The volume of optical module is decreased with the change of optical interface and connection form. In addition, the package of optical module is also developed from the metal package to the plastic package correspondingly.

3. Lower- Low Power Dissipation

In order to adapt to smaller and smaller volume of communication devices, interface density and interface boards, optical modules need to reduce power consumption. Using gallium arsenide technology, development technology, preamplifier can make chip product with silicon germanium reduce power consumption. In addition, the non-cooling laser can further reduce the power consumption of the optical module.

4. Farther - Longer Transmission Reach

On account that the laying distance of optical network is longer, the transmission distance is also required longer. The typical remote optical module without the condition of amplification can transmit 100km. But due to that there exists some certain loss and dispersion in the transmission process of optical signal on the fiber, the transmission distance of optical transceiver will be limited. After that, many remote optical transceiver module will choose to the working frequency band of 1550nm to make the transmission distance longer.

5. Simplified Management- Hot Plugging

Hot plugging means that the optical module can connect or disconnect with a device without cutting off the power supply. The network manager can upgrade and expand the system without closing the network, and it does not affect the online user. Hot plugging also simplifies the maintenance work and enables the end-users to manage their optical modules well. At the same time, because of the heat transfer performance, optical module allows network managers to formulate the link distance, transmission costs and all network topology according to the network upgrade requirements, without changing all system boards.

In order to meet the needs of people, optical module is developed towards the direction of "faster, smaller, lower and farther". As the main series of optical transceiver, SFP, SFP+, XFP, QSFP+, CFP/CFP2/CFP4, QSFP28 and other optical modules produced by Gigalight, are also constantly innovated under the guide of the development trend，in the great favor of the vast number of users.

Differences of QSFP28 PSM4, QSFP28 SR4 and QSFP28 LR4 Optical Transceiver

100G QSFP28 optical transceiver is the rising star in the 100G Ethernet. It is with the same appearance as the 40G QSFP+ transceiver. What is the difference between them is that QSFP28 optical transceiver module is with a 4*25G electrical interface which can transmit optical signals up to 100G. Therefore, the QSFP28 transceiver stands out as the mainstream of 100G optic fiber module and also as the first solution for option to upgrade 100G network. With respect to 100G QSFP28 optical transceiver, there are many series for choice, such as 100G QSFP28 PSM4, 100G QSFP28 SR4 and 100G QSFP28 LR4. Then in this post, there will be an introduction to the difference of QSFP28 PSM4, QSFP28 SR4 and QSFP28 LR4.

The Difference in Definition

The QSFP28 PSM4 optical transceiver is with high-speed, low-power-dissipation product with a hot-pluggable QSFP form factor and built-in digital diagnostics function. Besides, it is with eight optic fibers, each fiber with a data rate of 25Gbps.

The QSFP28 SR4 optical transceiver is a parallel 100G optical transceiver with the advantages such as high port density and low cost. If a optical module for the short-reach transmission is needed to upgrade 100G network, the QSFP28 SR4 optical transceiver can be chosen.

The QSFP28 LR4 optical transceiver is one with transmission distance up to 2km. It provides an ideal solution for the super-large-scale data centers which has ever-increasing requirements for transmission distance. Simultaneously, it will lead the use of single-mode optic fiber in the data center.

The Difference in Transmission Media and Distance

The three modules can support different transmission distances. 100G-SR4 QSFP28 module works over wavelength of 850nm and is used with 12-fiber MTP OM3 or OM4 multimode fiber cables for short transmission distances up to 100m. 100GLR4 QSFP28 module is suggested to be used with single-mode fiber. It works over 1310nm wavelengths and can transmit 100G signals up to 2km. 100G-PSM4 QSFP28 is also used with 12-fiber MTP fiber cables but the fiber type is single-mode and the transmission distance is up to 500m.

The Difference in Transmission Mode

It is known that QSFP28 modules generally use four lanes to transmit 100G with each lane supporting 25G. Thus, the transmission method is just like 40G QSFP+ transceiver. 100G QSFP28 SR4, LR4 and PSM4 all use the 4*25 transmission mode. However, both the QSFP28 SR4 and QSFP28 PSM4 use a 12-fiber MTP interface which achieves dual-way 100G transmission over 8 fibers at the same time. QSFP28 LR4 uses a LC duplex fiber optic interface for 100G transmission on two directions at the same time. QSFP28 LR4 transmit optical signals over four different wavelengths around 1310nm with each wavelength carrying 25G optical signal. The wavelength ranges of the four lanes are as following:

1294.53nm-1296.59nm

1299.02nm-1301.09nm

1303.54nm-1305.63nm

1308.09nm-1310.19nm

The Difference in Cabling Structure

Optical transceiver transmission has playing a very important role in the optical fiber routing. Because the QSFP28 SR4 optical transceiver and the QSFP28 LR4 optical transceiver are used for short-distance transmission and long-distance transmission respectively, their wiring structures are different. The former requires multi-fiber cabling based on a 12-way MMF MTP interface, while the latter requires only a traditional two-fiber SMF cabling. In this case, the conversion between multimode fiber and single-mode fiber is very complicated because they use a completely different wiring structure.

Although the QSFP28 PSM4 optical transceiver operates in single-mode fiber, its wiring structure is the same as that of the QSFP28 SR4 optical transceiver. Using the QSFP28 PSM4 optical transceiver saves conversion costs between multimode and single-mode without changing existing cabling structures.

The Difference in Working Principle

(1) Working Principle of QSFP28 PSM4:

The QSFP28 PSM4 optical transceiver works in much the same way as the QSFP28 SR4 optical transceiver. The difference is that the QSFP28 PSM4 optical transceiver operates on single mode fiber while the QSFP28 SR4 optical transceiver operates on OM4 multimode fiber.

(2) Working Principle of QSFP28 SR4:

QSFP28 SR4 optical transceiver transmits signals at the transmitting end; the electrical signals are converted into optical signals by the laser array and then transmitted in parallel on the ribbon multimode fiber. Upon reaching the receiving termination, the photo detector array converts the parallel optical signals into parallel Electrical signals.

(3) Working Principle of QSFP28 LR4:

QSFP28 LR4 optical transceivers are typically used with LC single-mode fiber optic cables to convert 4 25Gbps electrical signals into 4 LAN WDM optical signals and then multiplexed into a single channel for 100G optical transmission. At the receiving end, the module demultiplexes the 100G optical inputs into 4 LAN WDM optical signals, which are then converted into 4 electrical signal output channels.

Conclusion

Generally speaking, the differences of QSFP28 PSM4, QSFP28 SR4 and QSFP28 LR4 optical transceiver are as above mentioned. If you want to know more other information about them, maybe you can visit Gigalight at gigalight.com.

The Latest QSFP28 Optical Transceivers: QSFP28 4WDM and QSFP28 ER4 Lite

The 100G optical module is with a variety of packaging forms, mainly including the early CFP/CFP2/CFP4 and the new-generation QSFP28. As a hot solution of 100G network, CFP series and QSFP28 optical transceiver have their own advantages. They all play a role in the specific application of 100G network. Currently, it seems that QSFP28 series optical transceiver is in greater favor than CFP series opticcal module transceiver. With respect to QSFP28 series optical module, there are two new types: 100G QSFP28 ER4 Lite optical transceiver module and 100G QSFP28 4WDM optical transceiver module. Then Gigalight will have an introduction to them in this article.

An Introduction to QSFP28 4WDM Optical Transceiver

4WDM(4-Wavelength Wavelength Division Multiplexing) optical module is defined by 4WDM MSA, targeted for longer reaches, lower costs, and lower power consumption, smaller form factor(QSFP28 form factor is usually preferred). 100G QSFP28 4WDM optics have three specifications including 4WDM-10, 4WDM-20, 4WDM-40. 4WDM-10 is one type of 100G (4x25G) optical transceivers for the 10 km based on the CWDM4 wavelength grid; 4WDM-20 and 4WDM-40 are types of 100G (4x25G) optical transceivers respectively for 20kms and 40kms based on the LAN-WDM wavelength grid over duplex single-mode fiber (SMF). With respect to the benefits of 4WDM, its main advantages are lower in cost and power dissipation, and longer in transmission distance.

An Introduction to QSFP28 ER4 Lite Optical Transceiver

IEEE 802.3ba defines that the 100GBASE-LR4 / 100GBASE-ER4 series has a BER requirement of better than 1E-12 w / o FEC for optical modules. Since the receiving sensitivity of 100GBASE-ER4 is not satisfied with the existing APD technology, the SOA size is too large for the QSFP28 series; many optical module companies in the industry defined a non-standard 100GBASE-ER4 Lite with QSFP28 package that the largest transmission distance is up to 30km without FEC.

The receiving sensitivity of 100GBASE-ER4 Lite 30km has no clear definition in IEEE802.3ba. At the current level of 100G APD ROSA, the average of OMA Sensitivity is around -17dbm (BER 1E-12@25.78125Gbps). The description of the100GBASE-ER4 Lite products in the industry is defined as 30km w/o FEC, 40km with FEC.

100G QSFP28 ER4 Lite vs. 100G QSFP28 4WDM: What Are the Difference?

The differences between QSFP28 ER4 Lite and QSFP28 4WDM are shown as the table:

qsfp28 4dwm vs. qsfp28 er4 lite

In addition, in the aspect of application, 100G QSFP28 ER4 Lite is available for both 100GE and OTU4 application, while 100G QSFP28 4WDM 40km is only available for 100GE application.

Summary

The migration of current network infrastructure to 100G systems is inevitable, and a growing number of enterprises require 100G client port to extend up to 40km without the use of expensive optical amplifiers. Thefore, the new ER4 Lite and 4WDM optical transceiver enable cost-effective 100G 40km pluggable solutions in compact QSFP28 transceivers that use Forward Error Correction (FEC) and APD-based receivers. Such evolution is very exciting for not only everyone involved in its development and construction, but also for all those who seek a simple, reliable and cost-effective solution to extend the reach of their networks, without expensive network upgrades. Gigalight, as the design innovator in global optical interconnect field, has pushed out the latest 100G QSFP28 4WDM 40KM optical transceiver and 100G QSFP28 ER4 Lite 40KM optical transceiver. More details are at Gigalight(gigalight.com)

A Brief Introduction to 4WDM Optical Transceiver

In current optical communication market, optical transceiver products are developed in the trend of high data transmission rate, longer reaches, lower power consumption, etc. To keep pace with the trend better, many new optical module products with high transmission rate and longer reaches emerge, such as the latest one, QSFP28 4WDM(4-wavelength Wavelength Division Multiplexing) optical transceiver. In this article, we will mainly talk about it.

What is 4WDM MSA?

The 4WDM MSA is an industry consortium dedicated to defining optical specifications and promoting adoption of interoperable 100G (4x25G) optical transceivers for 10 km based on the CWDM4 wavelength grid, and for 20 km and 40 km based on the LAN-WDM wavelength grid, over duplex single-mode fiber (SMF). These extended reaches are important for modern datacenter interconnects and mobile backhaul applications. The 4WDM MSA participants are responding to previously unmet industry needs for longer reaches, lower costs, and lower power consumption, as compared to previously available standards, in small form factors.

An Introduction to 4WDM Optical Module

4WDM(4-Wavelength Wavelength Division Multiplexing) optical module is defined by 4WDM MSA, targeted for longer reaches, lower costs, and lower power consumption, smaller form factor(QSFP28 form factor is usually preferred). 4WDM optics have three specifications including 4WDM-10, 4WDM-20, 4WDM-40. 4WDM-10 is one type of 100G (4x25G) optical transceivers for the 10 km based on the CWDM4 wavelength grid; 4WDM-20 and 4WDM-40 are types of 100G (4x25G) optical transceivers respectively for 20kms and 40kms based on the LAN-WDM wavelength grid over duplex single-mode fiber (SMF). With respect to the benefits of 4WDM, its main advantages are lower in cost and power dissipation, and longer in transmission distance.

Specifications of 4WDM Optical Module: 4WDM-10, 4WDM-20, 4WDM-40

The 100G-4WDM-10 is based on the CWDM4 wavelength grid. To some degree, the 100G-4WDM-10 technical specification leverages the success of the CWDM4 2 km specification that has found broad acceptance in its target datacenter market. Like CWDM4, the 100G-4WDM-10 specification employs 4 lanes of 25Gb/s using Coarse Wavelength Division Multiplexing (CWDM) technology to transport 100G optical traffic across duplex single mode fiber (SMF). Both specifications take advantage of Forward Error Correction (FEC) on the host port, in accordance with IEEE 802.3bj KR4 RS FEC. One key advantage of CWDM is that the lasers do not need to be cooled or temperature controlled, resulting in lower power consumption and simplicity of manufacturing. 100G 4WDM-10 transceivers share these advantages and furthermore are specified to be fully interoperable with CWDM4 products. The 100G-4WDM-10 specification does not restrict the form-factor although high-density QSFP28 modules are expected to be dominant.

4WDM-20 and 4WDM-40 are added on the basis of the 100G 4WDM-10. They employ LAN-WDM wavelength grid on the basis of IEEE 100GBASE-LR4 and ER4, over duplex single-mode fiber (SMF). Simultaneously, they also utilize the IEEE 802.3 KR4 RS FEC used on the host interface to reduce the cost.

This specification defines 4 x 25Gbps Local Area Network Wavelength Division Multiplex (LANWDM)optical interfaces for 100Gbps optical transceivers for Ethernet applications including 100GbE. Forward Error Correction (FEC) is a link requirement in order to ensure reliable system operation. Two transceivers communicate over single mode fibers (SMF) of length from 2 meters to at least 20 or 40 kilometers. The transceiver electrical interface is not specified by this MSA but can have, for example, four lanes in each direction with a nominal signaling rate of 25.78125Gbps per lane.

In addition, the 4WDM-20 specification, which is an extension of the 100G-4WDM-10 10 km specification, enables customers to increase their reach using the same kind of optical components as 100GBASE-LR4 products. Similarly, the 100G-4WDM-40 enables 40 km reach with lower power consumption and in a smaller form factor than existing 100GBASE-ER4 compliant products that utilize a power-hungry SOA (Semiconductor Optical Amplifier).

Summary

It is commented by related expert that the new 20kms and 40kms specifications are an important milestone to enable this market. Thus, the prospect of 4WDM optical transceivers are worth expecting. For most of optical component suppliers, it means another opportunity. Gigalight, as the design innovator in global optical interconnect field, surely seizes the chance and pushes out one new product: QSFP28 4WDM 40KM. (About this product, you can click it or visit Gigalight website to know more).