3GPP 5G Standards 

The 5G standardization process is complex and highly innovative. 5G standards are developed in the 3rd Generation Partnership Project (3GPP), ITU Radiocommunication Sector (ITU-R), ITU Telecommunication Standardization Sector (ITU- T), the Internet Engineering Task Force (IETF) and IEEE. Here we focus on activities within 3GPP.


1.3GPP 5G will expand the LTE platform for new services while improving its efficiency to meet the mobile broadband demand.

2.3GPP 5G is not only a new radio (NR) interface but a full system, integrating LTE and NR radio access technologies with a 5G Core Network

  1. Initially, some of the use cases will be fulfilled by LTE, but the aim is to eventually fulfill all the requirements with NR
  2. From Release 15 onwards, the 3GPP specifications (LTE, NR and Core Network) will be marked “5G”

5.5G expands offerings by specializing radio and network capabilities (vertical sectors):

– Enhanced Mobile Broadband

– Massive Internet of Things

– Ultra-Reliable & Low Latency

Recent 3GPP 5G Developments

  • In September 2017 3GPP RAN plenary re-enforced the timeline commitment for 5G development set out in March 2017.
  • The focus for the “early drop” (December 2017) – Focus on LTE-anchored LTE-NR Dual Connectivity (DC) – Nonstandalone (NSA) NR – Several functions moved beyond December 2017
  • Focus for the full Release 15 in June 2018: Standalone (SA)NR with new 5G Core

–NSA and SA share common 5G NR physical layer specifications for the air interface, and, thus, these aspects were covered in the December 2017 milestone.

–The main focus for the SA standardization is on the upper layers with full user and control plane capability and on the next-generation core network architecture, including network slicing.

According to the plan of 3GPP, 5G standards are divided into NSA (Non-Standalone) and SA (Standalone). Among them, the Non-Standalone, which is to say the 5G networks will be supported by existing 4G infrastructure.

5G SA and NSA Standard

The 5G SA Standard

More than 600 delegates from the world’s major telecom operators, network, terminals and chipset vendors, internet companies and other vertical industry companies have witnessed this historic moment for 5G.

As the Release 15 work has matured and drawn close to completion, the group’s focus is now shifting on to the first stage of Release 16, often referred to informally as ‘5G Phase 2’. Among them, R15 mainly meets the application needs of Enhanced mobile broadband (eMBB) and Ultra-Reliable Low-Latency Communication  (URLLC). This stage is divided into two sub-stages. The first sub-stage 5G NR (New Radio) NSA feature was completed in December 2017 and frozen in March 2018. The second sub-phase, 5G NR standard, was completed in June 2018 and frozen in September.

The formulation of 5G NR standard means that the deployment standard of the whole 5G network has been improved, which will lead the industry to realize the commercialization of 5G communication and serve as the core infrastructure for the fourth industrial revolution in the future. As the first phase of 5G international standard, R15 can realize all the new features of 5G, which is conducive to giving full play to the full capacity of 5G. It is a truly commercially-oriented 5G standard and has some synergies with the final version of 5G R16 standard.

The 5G NSA Standard

Previously, in order to support national and national operators to achieve pre-commercialization of 5G in 2019, 3GPP completed 5G NSA standard ahead of schedule in December 2017 to support operators to carry out 5G mobile broadband business on the basis of the existing 4G core network. The released SA standard completes the 5G core network architecture and realizes 5G independent networking. SA standard can achieve the characteristics of 5G such as high reliability, ultra-low time delay and high efficiency, which is the core attribute of 5G to penetrate into the medical, industrial Internet, Internet of vehicles and other industries.


5G is a key milestone in the history of optical communication. For 5G optical networks, there is a huge market with so many challenges. Gigalight will keep providing customers with high-speed optical interconnection products with innovative designs and leading solutions.

Gigalight has launched a series of industrial-grade optical transceivers such as  25G BiDi SFP28 LR, 25G CWDM SFP28 LR25G DWDM SFP28 optical transceivers for 10km/20km applications in the 5G fronthaul network, and 100GBASE-LR4/4WDM-40 QSFP28 modules along with 200G QSFP56 LR4 used for 10km applications in 5G midhaul (and backhaul) network. At the same time, we also offer industrial-grade passive optical components such as 5G OMUX, CCWDM, and AAWG.

The Path to Upgrade Data Center

With the increasing demand for high bandwidth from private cloud, public cloud data center and service providers, 25G and 100G are widely used. 200G and 400G optical devices will be successively produced and shipped from 2019. So far, most server vendors have started offering servers 25G of fiber-optic network CARDS as an I/O(input/output) option, and Ethernet’s signal transmission rate has increased from the earlier 10G to 25G, 100G or higher. While 1G, 10G and 40G currently dominate the Ethernet port market, the future demand for 25G and 100G is stronger than ever as high bandwidth is undeniably driving data centers toward greater scalability and flexibility.

Why Is 25G Coming to Data Centers?

Data centers are expanding at an unprecedented rate, driving the need for higher bandwidth connections between servers and switches. To accommodate this trend, the access network has been upgraded from 10G to 25G, providing high-density, low-cost, and low-power solutions for the connection between servers and ToR switches.

The Development History of 25G

Since its advent in 2014, Google, Microsoft, Arista Networks, Broadcom, and Mellanox have been driving the development of the 25G Ethernet standard, which is intended to enable a 25G top-shelf server network. With the increasing popularity of 25G and its rapid spread in the market, 25G will provide a comprehensive solution for the connection between server and switch in the future.

The Advantages of 25G

Before the release of 25G Ethernet standard, enterprises, operators and other data centers generally adopt the network upgrading method of 10G to 40G. With the official release of 25G Ethernet standard, 25G to 100G network upgrading method has gained more applications with the advantages of low cost, low power consumption and high density, promoting the rapid development of 100G Ethernet. Let’s take a look at the differences between 10G, 25G, 40G, and which upgrade is superior.

25G Can Provide Higher Performance Bandwidth Than 10G

In the current data center, the network connection between the server and the switch is generally between 10G and 25G. Compared with 10G, 25G is an improvement based on 10G packaging and chip technology, providing higher bandwidth and performance. The emergence of 25G enables the data center to be based on the existing network architecture without any cable interconnection, and can also support the transmission of higher rate (over 10G), meet the demand for higher bandwidth in the future network, and make the network upgrade more convenient and easy. The wiring infrastructure required for 25G and 10G transmission is basically the same, which can effectively avoid the expensive cost and the complexity of rewiring and make the network upgrade more convenient.

In addition, the 25G is similar to the 10G in that it uses a single channel of SerDes for backward compatibility, significantly reducing power consumption and costs and helping data center operators save capital and operating expenses.

Insert 25G SFP28 optical transceiver into 10G SFP+ port, what speed will we get?

Theoretically, the 25G SFP28 optical transceiver is backwards compatible with 10G SFP+ port, and its rate can reach 10G/s. However, this mode of use is not suitable for all brands of switches and optical transceivers. Considering the limitation of the fiber network card and switch port, this mode is generally not recommended.

25G Is More Suitable for High-density Requirements Than 40G

For large, high-end enterprises, the port density of the server largely determines the cost of cabling and switch infrastructure in the whole system. Therefore, compared with 40G, the cost of upgrading from 25G to 100G is relatively low. Because 25G to 100G network upgrade, the switch port is fully utilized, effectively reducing the cost of bandwidth.

It has been upgraded to a 40G network. Is it necessary to deploy a 25G network?

25G devices are expensive compared to 40G devices, so having upgraded to a 40G network, is it necessary to deploy a 25G network? Due to the cost rationalization of the 25G channel, 25G is definitely an important path to upgrade from 10G to 100G or higher in the future. If you need to increase the baud rate (signal transfer rate) or plan to upgrade the network to a higher speed (100G/200G/400G), then you must deploy the 25G network. If there is no requirement, then you do not need to deploy the 25G network.

The Prospect of 25G

At present, 25G servers and 100G switches can be seen everywhere in very large data centers. They gradually replace the earlier 10G servers and 40G switches. This network upgrade increases the throughput of the whole system by 2.5 times and reduces the incremental cost of equipment. As the Ethernet industry continues to innovate and lay the foundation for higher rate research and development, the 25G-100G upgrade model has become an important path for data centers.

25G Offers More Possibilities for 50G

As we all know, 25G can provide 2.5 times the bandwidth compared with 10G, and 50G can provide 1.25 times the bandwidth compared with 40G in the future. Currently, 50G has been proposed as the basis for 100G,200G, 400G network upgrade, but the implementation of 50G Ethernet standard still needs some time.

25G will provide more possibilities for 50G, as the implementation of 50G Ethernet can be based on two 25G channels, so it will be an alternative to the current use of four 10G channels up to 40G, reducing the cost of network equipment in the data center by reducing channel deflection. In the future, the network upgrade path may evolve from the traditional 10G-40G-100G to 10G-25G-50G-100G. In any case, upgrading a data center from multiple 25G channels to a 50G or 100G network will be simpler and more economical.

25G Lays the Foundation for 200G and 400G Network Upgrade

The 25G,50G,100G network architecture offers greater flexibility and is often used as a solution for large data centers, paving the way for later 200G/400G upgrades. At present, high-end enterprises and large data centers are shifting towards this, effectively promoting the implementation of large data centers and the interconnection between data centers. Nowadays, more and more suppliers in the market are engaged in the research and development of 200G and 400G optical devices, some of which have been successfully put into use. The implementation of 100G Ethernet is based on the development of 25G/50G. Similarly, the future network upgrade of 200G and 400G will be based on 100G. The following table lists the paths from 25G/50G/100G to 200G/400G.


The need for higher speed and performance in future data centers will never cease. Looking back at the evolution of 25G over the past few years, you can see that the emergence of 25G is a milestone in the next generation of data center network bandwidth and channel capacity expansion. The 25G to 100G network upgrade overturns the traditional 10G-40G network and improves the efficiency of the data center by providing higher bandwidth and port density, reducing power consumption and cost. It lays a solid foundation for the 200G/400G upgrade. Let’s wait and see how the continuous development and innovation of Ethernet will promote the new round of changes in the data center.

Gigalight supplies one-stop data center optical transceivers for 40G/50G/100G/200G/400G Ethernet interconnections. Gigalight has been keeping pace with the industry’s mainstream technology, focusing on boutique development to help users create a high-capacity, high-reliability, large cache cloud data center network. In the future, Gigalight will bring more innovative products to customers.


Three Hot Selling 200G Optical Transceivers for Data Center



The dramatically grew in demand for 100G CWDM over the past year. While 100G continues to ramp, the promise of high volume 400G remains omnipresent, albeit a 2019 phenomenon. Customers need existing technologies that ship in production volumes to fill this industry gap. While 100G CWDM is a mature and well-understood technology and will continue to ramp in the coming year, many of the big Cloud Data Center OEMs are turning their sights to 200G, to meet the pressures of enabling faster connections at scale volumes.

200G optical transceivers with their many advantages such as significantly lower latency, power consumption and cost are coming to market now, and are seen by many as a viable, volume-scalable stepping-stone to 400G. The three hot selling 200G optical transceivers for the data center will be introduced in this article.

No. 1


QSFP-DD ports are backwards compatible with QSFP28 which is very important to provide a smooth upgrade path and links with older systems.  The backwards compatibility of the QSFP-DD allows for easy adoption of the new module type and accelerate overall network migration.


It is a high-performance module for short-range multi-lane data communication and interconnects.

The Gigalight 200G QSFP-DD SR8 NRZ optical transceiver is designed for 2×100-Gigabit Ethernet 100GBASE-SR4 applications. The 200G QSFP-DD SR8 optical transceiver is designed to operate over multimode fiber systems using a nominal wavelength of 850nm. This module incorporates Gigalight proven circuit and VCSEL technology to provide reliable long life, high performance, and consistent service. Historically VCSEL-MMF links have been seen by many as the lowest cost short-reach interconnect.

No. 2


The form-factor for 200G QSFP-DD PSM8 NRZ optical transceivers are similar to 200G QSFP-DD SR8 NRZ.


It is a high-performance module for data communication and interconnects.

The Gigalight 200G QSFP-DD PSM8 NRZ optical transceiver is designed for 2×100-Gigabit Ethernet PSM4 and InfiniBand DDR/EDR applications. The 200G QSFP-DD PSM8 (dual PSM4) module integrates eight data lanes in each direction. Each lane can operate at 25.78Gbps up to 2km/10km over G.652 SMF. It is designed to operate over single-mode fiber systems using a nominal wavelength of 1310nm. The electrical interface uses a 76-contact edge type connector. The optical interface uses a 24-fiber MTP/MPO connector. This module incorporates Gigalight proven circuit and optical technology to provide reliable long life, high performance, and consistent service.   

 No. 3

200G QSFP56 SR4 PAM4

PCB layout and heat dissipation design are crucial challenges for 200G QSFP56 SR4 PAM4. Too many components, smaller QSFP56 package and the larger thermal power consumption which are the main reasons.

200G QSFP56 optical transceiver represents an evolution of the highly popular four-lane QSFP+ form factor is ideally suited for hyperscale data centers and high-performance computing (HPC) environments.


It is compliant with the QSFP MSA and IEEE 802.3cd 200GBASE-SR4 specification.

The Gigalight 200G QSFP56 SR4 PAM4 optical transceiver is designed for  200-Gigabit Ethernet links over multimode fiber. This transceiver is a high-performance module for short-range multi-lane data communication and interconnects. It integrates four data lanes in each direction with 212.5Gbps bandwidth. Each lane can operate at PAM4 53.125Gbps (26.5625GBd) up to 70m using OM3 fiber or 100m using OM4/OM5 fiber. These modules are designed to operate over multimode fiber systems using a nominal wavelength of 850nm. The electrical interface uses a 38-contact edge type connector. The optical interface uses a 12-fiber MTP/MPO connector. This module incorporates Gigalight proven circuit and VCSEL technology to provide reliable long life, high performance, and consistent service. 


200G and even 400G transceivers will start to be commercially adopted starting 2019 and will start taking away the market share from the 100Gbps transceivers. 2019 will be a pivotal year to see how 200G takes hold in the cloud datacenter, and intensifying industry collaboration on 200G standards and interoperability could help position this technology for sustained mainstream adoption while 400G continues to mature.  

Which One Is the Option for 5G Fronthaul? 10G, 25G or 100G? 


5G is expected to be implemented in the following years. To have this 5G network realized, optical communication will be the cornerstone technology independent of various fronthaul options. The demand for high-rate optical transceivers will significantly increase because higher base-station density is required for the 5G network.

Although it is still not clearly determined which fronthaul architecture will be used in the 5G network, it is apparent that the network would employ both grey and color optics for 25Gbps based on 5G bandwidth requirement.

Grey and Color Optics

The light in WDM systems is carried over different wavelengths compliant with specific standards.

To distinguish wavelengths in different systems, the wavelengths in WDM systems are called colored light whereas the wavelengths in common optical systems are called grey light.

Grey light is within a certain wavelength range and does not have a standard wavelength, for example, the light at client-side optical ports of WDM devices.

Colored light is WDM-side optical signals of the OTN or line boards in a WDM system. The signals can be directly transmitted to multiplexer devices and have standard wavelengths.

Colored light is divided into CWDM and DWDM light, depending on wavelength division standards.

For 5G network, Gigalight has a complete portfolio of 10Gbps and 25Gbps optical transceivers that are tailored for upcoming standards such as eCPRI/NGFI as well as traditional CPRI options.

Gigalight 25G SFP28 transceivers also play in a critical role in the growing bandwidth demand in next generation access networks such as 5G wireless. While interface developments, like the recently released eCPRI specifications, will help improve bandwidth efficiency, the 5G wireless infrastructure will require significantly higher capacity in the optical links. Compact,  power and cost-efficient 25G transceivers supporting both Ethernet and CPRI-10 while exposed to the elements will play a key role in supporting the rollout of this next generation wireless infrastructure.


At present, 10G optical transceivers were mainly used in LTE base stations.  In the 5G network, it is expected that 25G and even 100G optical transceivers shall be the preferred solutions of the optical fronthaul network.

Vietnam–First 5G Call

The first call using fifth generation (5G) technology in Vietnam was successfully conducted by Telecom giant Viettel and Sweden’s Ericsson Group on May 10. Vietnam as one of the few countries in the world that has successfully tested the 5G technology, after the US, Australia, Japan and South Korea.

5G is an opportunity for Vietnam to improve its ranking in the world.

Vietnam wants to be at the forefront of the Fourth Industrial Revolution and develop the ICT sector, so that Vietnamese people and businesses can compete in the global economy.

Vietnam has been seeking to bring 5G into commercial operation in 2020 and will be one of the first countries to deploy the latest network.

Vietnam’s 5G Development Strategy

In the first phase of 5G–Smart factories

Viettel and other network providers must experiment to cover 5G in all hi-tech zones, national innovation centres and smart factories by 2020.

In terms of transmission infrastructure

IoT technology based on 4G LTE-M and NB-IoT has been deployed by Viettel to become one of the first 50 operators in the world to deploy these technologies.

Artificial intelligence

Viettel is ready to apply artificial intelligence solutions to solve social problems.

Network security

Viettel also builds the largest and most sophisticated network security team in Vietnam to protect the safety of users on the internet.


Ericsson has accompanied Viettel in the experimental implementation of 5G. Viettel and Ericsson acknowledged the importance of using 5G in applying and improving the benefits of Industry 4.0. It was expected to promote digitalization in all sectors including production, agriculture, energy, healthcare and education.

By bringing 5G services to Vietnam early, Viettel and Ericsson have been building a foundation for Industry 4.0. 5G will provide important infrastructure to create momentum and allow Vietnam to attract more FDI in the hi-tech sector. About 5G news, Gigalight will continue to update the latest information about various countries for you.

200G Optical Modules for the Next-generation Data Center Deployments

With 100G in wide-scale deployment today and the promise of mainstream 400G deployment seemingly ubiquitous, Cloud Data Centers are eager to take advantage of any and every opportunity to bridge the throughput gap and keep pace with the data deluge. 200G (4 x 50G) optical modules answer this immediate need head-on.

At the broader market level, while 100G technology is already mature and component integration is well established, 200G end-to-end interoperable chipsets have just recently hit the market. Looking to the past as our guide, in the short term, 200G modules are expected to emulate cost structures akin to 100G modules when they entered the market a few years ago and follow a similar downward cost curve as component integration is further standardized and volume shipments accelerate. In due course, 200G modules are expected to achieve a cost structure that’s comparable to today’s 100G modules.

While 100G CWDM is a mature and well-understood technology and will continue to ramp in the coming year, many of the big Cloud Data Center OEMs are turning their sights to 200G, to meet the pressures of enabling faster connections at scale volumes. 


Google started deployments in 2x200GbE transceivers in 2018 and we expect that demand for these products will peak in 2022, as Googles starts to transition to 2x400GbE modules.


The forecast for 400GbE includes 4x100GbE DR4 modules selected by Amazon. These DR4 modules will be deployed in a breakout configuration with DR1 modules on the opposite side of the link. Effectively, each fiber will be carrying 100GbE traffic, aggregated into a DR4 module on one side. Deployments of true 400GbE transceivers will be limited in 2019-2021 to upper levels of switching in mega-datacenters and core routers. Implementation of high-radix configurations in leaf and spine networks using 400GbE connectivity will be challenging until switching ASICs reach 51Tbps capacity, probably by 2022-2023.


Facebook is staying with 100GbE for now and plans to use 200GbE next.

More than 2.6 billion people now use its services.

Facebook publicly stated their intent to stay with 100GbE optics for now and use 200GbE or 400GbE transceivers in the next upgrade cycle in 2021-2022. Facebook’s new F16 data center network architecture, will require 3-4 times more optical connections compared to their previous design (F4). The first implementation of F16 topology will rely on 100GbE CWDM4 transceivers, boosting demand for these modules in 2020-2022. 

Facebook is already the largest consumer of 100GbE CWDM4 modules. They use a sub-spec version of CWDM4 transceivers with 500-meter reach instead of 2km, also known as CWDM4-OCP (for Open Compute Project). The latest forecast database includes sub-spec CWDM4 modules as a separate category. Segmenting the sub-spec products also helped us to refine the market data collected for 2018, resulting in higher than previously reported sales.

Once these issues are resolved, the demand for CWDM4 is expected to skyrocket in the second half of 2019 and make a real difference to the market in 2020-2022. Sales of sub-spec CWDM4 modules are projected to peak in 2022, as Facebook starts the transition to 200GbE connectivity.


Though intermediate between 100G, and 400G – the customer demand for 200G, is shaping this market to be sizable, with deployments expected by the second half of next year. The good news for module vendors is that there are multiple component vendors, such as MACOM, who have 200G compatible components on the market today. 

Comparing the cost for 100G versus 200G, we have to look specifically at the cost of components themselves. While 100G is already at the point of integration, 200G end-to-end operable chipsets have just hit the market. 200G will therefore emulate a similar price point as 100G did when it entered the market a few years ago, following a similar cost curve as integration furthers. 

Gigalight is committed to leading the evolution of Data Center interconnects from 100G to 200G and 400G. Gigalight 200G products such as 200G QSFP-DD SR8 NRZ 100m, 200G QSFP-DD PSM8 NRZ 2km, 200G QSFP-DD PSM8 NRZ 10km, 200G QSFP56 SR4 PAM4 100m, 200G QSFP56 FR4 PAM4 2km, 200G QSFP56 LR4 PAM4 10km and so on. Among them, the Gigalight 200G QSFP-DD PSM8 NRZ 10km optical transceiver (GDM-SPO201-LR8C) is an eight-channel, hot-pluggable, parallel, fiber-optic QSFP Double Density module designed for 2×100-Gigabit Ethernet PSM4 and InfiniBand DDR/EDR applications. It is a high-performance module for data communication and interconnects.

The 200G QSFP-DD PSM8 (dual PSM4) module integrates eight data lanes in each direction. Each lane can operate at 25.78Gbps up to 10km over G.652 SMF. It is designed to operate over single-mode fiber systems using a nominal wavelength of 1310nm. The electrical interface uses a 76-contact edge type connector. The optical interface uses a 24-fiber MTP/MPO connector. This module incorporates Gigalight proven circuit and optical technology to provide reliable long life, high performance, and consistent service.


Source: LightCounting

5G Is Driving the Evolution of Optical Transceiver Industry


We are now starting to see commercial 5G networks going live. Previous generations were focused on consumer and personal communications but now 5G will serve consumers, enterprises and take the internet of things to the next level, where superior connectivity is a prerequisite. Initially, 5G will be a capacity enhancer in metropolitan areas and enhanced mobile broadband and fixed wireless access will be ways for operators to address explosive traffic growth.

According to LightCounting, 5G will drive significant growth in the global market for optical transceivers since 2019, especially in China. At the same time, the demand for low-speed optical devices below 10G will gradually decrease and increase in the demand for transceivers of 25G, 50G, and 100G.

The change of optical transceiver demand is driven by 5G revolution. RAN architecture of the 5G system will realize the separation of CU and DU, which determines that 5G wireless network will include fronthaul, midhaul and backhaul. New requirements are proposed in terms of the amount of optical transceiver and the technical requirements of the optical transceiver.

Optical transceivers Need to Be Able to Meet the Requirements for Bearer Network in 5G Era


The transmission distance should be within 10km or even shorter. The operating temperature should reach industrial temperature and the CPRI interface rate should reach 25Gbps.


The transmission distance should be at least 10km and the operating temperature should reach the commercial temperature. Gray optical transceiver or BiDi is mainly considered. In addition, 50G PAM4 may be a good choice.


The transmission distance should be more than 10km and the operating temperature should reach the commercial temperature. The 100G, 200G, 400G rate optical transceiver is mainly used. In addition, WDM or coherence technology will be taken into consideration.


Since the evolution of CPRI interface to PRI will lead to an increase of RRU power consumption, more heat-resistant optical transceivers are needed. In addition, the wireless architecture will evolve from DRAN to CRAN, and there will be a shortage of optical cable resources, which requires more energy-saving optical transceivers. In addition, 5G will use a higher frequency band, the coverage will be smaller, and the number of optical transceivers will be greatly increased so that the low-cost optical transceivers are needed. At the same time, 5G’s spectrum bandwidth increases transmission bandwidth, and higher speed optical transceivers are needed to meet this demand.


All in all, the core requirements for optical devices in wireless scenarios are mainly reflected in higher operating temperature range, less fiber resource consumption, lower cost, and faster single wave rate.


How to meet these needs of optical transceivers in the 5G era?

The solutions for High-temperature transceiver — industrial temperature light chip and silicon light can make the optical device itself work at high temperature, and can guarantee rapid heat conduction through good thermal design.

The solutions for optical fiber resource shortage—the most obvious solution is to use BiDi, which can save 50% of the optical fiber resources and thus use the existing optical fiber resources to transmit twice the bandwidth. Passive WDM solutions are also available.


Building on the success of the company’s 10G CWDM SFP+

transceiver and 10G DWDM SFP+ transceiver, Gigalight developed its next-generation 25G CWDM  in an SFP28 form factor. And Gigalight 25G SFP28 BiDi optical transceivers are available. This technology is believed to be a key building block for deploying these transceivers and is designed to enable cost-effective next-generation 5G wireless build-outs while also providing significantly more data capacity per fiber than other 25Gbased optical architectures. This will enable Transceiver-to-transceiver communications and self-wavelength tuning of remote transceivers during commissioning without host interaction, so field installation and remote maintenance are simplified and operational expenses are lowered.


According to different scenarios, there are different requirements for optical transceivers. The traditional optical device technology in the field can meet the current needs, but there is a trend to update the technical field of evolution. At the same time, the realization path of the growth of optical transceiver rate also presents a diversification trend. Finally, no matter what you need are, Gigalight is here to create, assist and innovate.

In Case You Missed the Questions for 25G Transceiver


Here’s a frequently asked question to address questions that have arisen from the significant uptick in the use of 25G transceivers, which is driven by high bandwidth demands in the enterprise, data center and service provider applications.

1. Why is the use of 25G increasing?

Many network operators have chosen 25G instead of multiple 10G’s because 25G provides 2.5x bandwidth of the 10G in the same familiar SFP form factor at approximately the same power. This has enabled network equipment manufacturers to provide higher bandwidth connectivity. Rack-mountable switches and routers populated with 12 ports, 24 ports, and 48 ports on a single 1 RU faceplate are common for SFP.


2. What is the cost per bit of 25G?

25G provides 2.5x the bandwidth of 10G at a slight increase in cost. The result is nearly a 50% reduction in the cost per bit.

3. Is 25G standardized?

The IEEE (Institute of Electrical and Electronic Engineers) has standardized 25G. See IEEE802.3by and IEEE802.3cc for the details.

4. Which popular Gigalight’s 25G transceivers are available today?

25G SFP28 SR 100mIndustrial

25G SFP28 LR 10km Industrial

25G SFP28 ER Lite 20km Industrial

25G LWDM SFP28 ER 40km Industrial

25G SFP28 BiDi 10km Industrial

25G SFP28 BiDi 20km Industrial

25G CWDM SFP28 10km Industrial

5. What is SFP28?

SFP28 is the standardized pluggable form factor for 25G transceivers. It has the same mechanical dimensions as 10G SFP+ and 1G SFP. The electrical interface of 25G was envisioned to operate up to 28Gbps to accommodate overhead for a 25Gbps signal.  Today most 25G transceivers operate at a 25.78125Gbps nominal data rate. The standards body that defines SFP28 is SFF (Small Form Factor Committee).

6. What is SR?

SR is Short Reach, and generally refers to transceivers that operate over MMF up to a few 100 meters.

7. What is LR?

LR is Long Reach, and generally refers to transceivers that operate over SMF at up to 10km.

8. What is ER?

ER is Extended Reach, the data rate of the transceivers support distance up to 40km over single mode fiber and use 1550nm lasers.

9. What is BiDi?

BiDi is called bi-direction as well. BiDi transceiver usually consists of two different wavelengths to achieve transmission in both directions on just one fiber (single-mode or multi-mode). Unlike general optical transceivers which have two ports, BiDi transceivers have only one port.

10. What is CWDM?

CWDM is Coarse Wavelength Division Multiplexer, a process of combining multiple wavelengths into a single fiber optical cable. Considering the smooth evolution of 5G equipment and the development of the industry chain, 25G CWDM SFP28 solution can well solve the current 5G millimeter wave pre-transmission problem.

11. What does “10/25G” mean?

These are dual-rate transceivers that support both 10G and 25G rates.

12. What New Technology Is in 25G Transceivers?

25G transceivers have CDR (Clock Data Recovery) circuits and generally require FEC (Forward Error Correction).

13. Where can additional information about Gigaligh 25G transceivers be found?

See the Gigalight 25G: https://www.gigalight.com/5g-fronthaul-optical-transceivers.html

WDM Technology Will Be Broadly Used in the Coming 5G



An Overview of WDM

WDM stands for Wavelength Division Multiplexing. WDM is the most important and most popular method to increase the capacity of a single strand of fiber.  

Traditionally, only one colored light was used on a single strand of fiber to carry the information, such as 1550nm light. However, starting from the early 1990s, the Internet boom pushed service providers to find a method to increase the capacity on their network in the most economical way. That is when WDM devices were invented.

In a WDM system, many different colored lights are combined by a WDM multiplexing device and put into a single strand of fiber, each color is called a channel.

On the receiver side, each color is separated into its own channel by a WDM de-multiplexing device. It shows that a single fiber’s capacity is increased by 40 times with a 40 channel WDM. The beauty of WDM is that you only need to upgrade the end equipment, no need to dig up trenches to bury more fibers, which is much more costly.   

Communication systems are designed differently, and the width of the gap between each wavelength varies. Depending on channel spacing, WDM can be subdivided into CWDM and DWDM.


CWDM supports up to 18 wavelength channels transmitted through a fiber at the same time. To achieve this, the different wavelengths of each channel are 20nm apart.

DWDM, supports up to 80 simultaneous wavelength channels, with each of the channels only 0.8nm apart. 

CWDM technology offers a convenient and cost-efficient solution for shorter distances of up to 70 kilometers.

For distances between 40 and 70 kilometers, CWDM tends to be limited to supporting eight channels. Unlike CWDM, DWDM connections can be amplified and can, therefore, be used for transmitting data much longer distances.


  • Wavelengths Used in WDM


DWDM is typically limited to 1450 to 1650nm

CWDM may operate over the full range of 1280 to 1650nm


  • Laser Source Spacing


DWDM uses lasers at ~0.8nm spacing

CWDM uses lasers at a 20nm spacing  

Advantages of WDM Technology

  1. Large transmission capacity can save valuable optical fiber resources. For single-wavelength optical fiber systems, a pair of optical fibers are needed to transmit and receive a signal, while for WDM systems, no matter how many signals there are, the entire multiplexing system only needs a pair of optical fibers. For example, for 16 2.5gb /s systems, the single-wavelength optical fiber system needs 32 optical fibers, while the WDM system only needs 2 optical fibers.
  2. It can transmit different types of signals such as digital signals, analog signals, etc., and can synthesize and decompose them.
  3. When the network capacity is expanded, there is no need to deploy more optical fiber, nor need to use high-speed network components, only need to change the end machine and add an additional wavelength of light to introduce any new service or expansion capacity, so WDM technology is an ideal means of capacity expansion.
  4. The dynamic reconfigurable optical network can be constructed, and the all-optical network with high flexibility, high reliability, and high survivability can be formed by using optical division multiplexer (OADM) or optical cross-connection device (OXC) at the network nodes.

WDM Technology Is Expected to Optimize Cost for 5G Development

The 5G wireless infrastructure necessitates wavelength division multiplexing (WDM) technology to optimize fiber usage. Fixed and reconfigurable multiplexing are two approaches that provide tradeoffs in terms of network scalability, reliability, and cost. Optical networks closest to the antenna are the most cost sensitive and can benefit from fixed WDM solutions. Gigalight’s broad portfolio of WDM modules is available in various configurations including coarse-WDM (CWDM), dense-WDM (DWDM) modules and other WDM solutions.  


Wavelength-tunable Optical Transceivers

What Is Wavelength-tunable Optical Transceiver?

Tunable optical transceivers are similar in operation and appearance to fixed transceivers, however, they have the added capability of allowing you to set the channel (or color) of the emitting laser. This reduces the need to have multiple devices that each operates at fixed wavelengths installed within a network. Instead, you have one transceiver that can be tuned according to the requirements of the operator.

Tunable transceivers are only available in DWDM form, because of the format of the dense wavelength grid. Typical tunable optics are designed for the C-Band 50GHz. They support approximately 88 channels which are set with a 0.4nm interval. They usually start from channel 16 and go up to 61, but this is dependent on the manufacturer of the router or switch and which channels it supports.

Tunable optical transceivers for DWDM systems have been widely available within the telecommunications industry for many years.

There are two main types of tunable transceivers such as XFP and SFP+. 
XFP Tunable

Tunable XFP transceivers are designed with an integrated full C-Band tunable transmitter and high-performance receiver. This means that wavelengths can be set as default in the 50GHz DWDM grid. With single mode fiber, XFP tunable transceivers can operate at distances up to 80km.

Depending on the manufacturer, the names for these products can vary even though they have the same operational features.

These optics can be tuned in different ways. Most devices make it possible to tune over the CLI (Command Line Interface), but not every switch or router is capable of this.

SFP+ Tunable

Tunable SFP+ transceivers are full duplex, serial optical devices. The transmit and receive functions are contained within a single module which provides a high-speed serial link at 9.95 to 11.3Gbps signaling rates.

Again, these products can operate at distances of up to 80km with single mode fiber.

What Are the Benefits of Tunable Transceivers?

As technology has progressed, tunable transceivers have improved drastically. They are now very popular within DWDM transmission systems because of their capabilities and ease of use.

The key benefits are:

Wide tuning range

Suitable for 100G systems because of reduced line-width

The convenience of wavelength adjustment depending on transmitting needs

Reprogramming takes seconds

Saves money in the long term


Tunable optical transceivers are able to operate at various wavelengths and adjust their wavelength according to each users’ needs. They are very popular in DWDM systems due to cost-saving factors and flexibility of use.

At Carritech, we stock and support a full range of optical transceiver products. To view our stock, learn more about our products or inquire about purchasing visit our optical transceiver page.

Gigalight can provide 10G tunable SFP+ and 10G tunable XFP optical transceivers. The 10G tunable SFP+ is with low power consumption, lower than 1.7W. The wavelength of this module is stable and the transmit optical power is about 0dBm. The extinction ratio is greater than 10dBm; the side die suppression ratio is greater than 51dB, the eye-diagram crossing point is between 47% and 52 %, and the sensitivity of this module can reach above -24dBm. It supports distance up to 80km. And the 10G tunable XFP can be piled into two versions to support FEC coding function (OTN G.709 framing) and non-FEC coding function. The power consumption of the former is less than 4.5W, and the advantage of the FEC coding function is to improve the sensitivity of transmission; while the power consumption of the latter without FEC function is less than 3.5W. The two versions are available to meet maximum distance of 80km as well as to be compatible with the switches and core routers of Cisco, Juniper, and other major equipment suppliers.