Unveiling the Types and Applications of 800G Transceiver

As the demand for faster data transfer continues to surge, 800G transceivers are garnering attention for their high bandwidth, rapid transfer rates, superior performance, high density, and future compatibility. In this article, we will offer an overview of the different types of 800G optical modules, explore their applications, and address some frequently asked questions to assist you in making an informed choice when selecting an 800G transceiver.

Types of 800G Transceiver

800G = 8 x 100G = 4 x 200G. Therefore, based on the single-channel rate, 800G transceivers can be broadly categorized into two groups: single-channel 100G and 200G. The diagram below illustrates the corresponding architectures. Single-channel 100G optical modules can be implemented relatively swiftly, whereas 200G optical modules entail greater demands on optical devices and necessitate a gearbox for conversion. This article primarily focuses on introducing single-channel 100G modules.

Single-Mode 800G Transceivers

The 800G single-mode optical transceiver is suitable for long-distance optical fibre transmission and can cover a wider network range.

800G DR8, 800G PSM8 & 800G 2xDR4

The three standards share a similar internal architecture, featuring 8 Tx and 8 Rx with a single channel rate of 100 Gbps and require 16 optical fibres.

800G DR8 optical module uses 100G PAM4 and 8-channel single-mode parallel technology, and the transmission distance through single-mode optical fibre can reach up to 500m, which is typically used in data centres, 800G-800G, 800G-400G, and 800G-100G interconnections. FS 800G QSFP-DD DR8 delivers exceptional performance for 800GBASE Ethernet applications, offering throughput of up to 800 Gigabits per second over eight pairs of single-mode fibres (SMF) with MPO-16 APC connectors, extending up to 500 metres. Fully compliant with IEEE P802.3ck, IEEE 802.3cu, and QSFP-DD MSA standards, this transceiver ensures seamless compatibility and reliable operation.

800G PSM8 utilises CWDM technology with 8 optical channels, each delivering 100Gbps, supporting 100m transmission distance, making it ideal for long-distance transmission and fibre resource sharing.

800G 2DR4 denotes 2x 400G-DR4 interfaces. It features 2x MPO-12 connectors, allowing 2 physically distinct 400G-DR4 links from each 800G transceiver without the need for optical breakout cables. As illustrated in the following figure, it can be linked to 400G DR4 transceivers and supports a transmission distance of 500m, thus facilitating data centre upgrades.

800G 2FR4/2LR4/FR4/FR8

800G FR and LR in these designations stand for Fixed Reach and Long Reach, representing fixed and long transmission distances, respectively.

800G 2xFR4 and 800G 2xLR4 are two additional standards with similar internal structures. They comprise 4 wavelengths operating at a single-channel rate of 100 Gbps. By utilizing Mux, the number of required optical fibres is reduced to 4, as depicted in the figure below. These standards were introduced as upgrades to the 400G FR4 and LR4 transceivers. They employ CWDM4 wavelengths at 1271/1291/1311/1331nm. 800G 2xFR4 supports a transmission distance of 2km, while 800G 2xLR4 supports a transmission distance of 10km. Optical interfaces for these standards utilise dual CS or dual duplex LC interfaces. They are both suitable for 800G Ethernet, breakout 2x 400G FR4/LR4, data centres, and cloud networks.

FS provides 800G 2xFR4 and 800G 2xLR4 modules in OSFP packages. FS 800G 2FR4 optical transceiver Module is designed for 800GBASE Ethernet throughput up to 2km over single-mode fibre (SMF) with duplex LC connectors. FS 800G 2LR4 transceiver supports up to 10km link lengths over single-mode fibre (SMF) via dual LC connectors. Both products have undergone rigorous testing and have excellent performance.

800G FR4 adopts a scheme employing four wavelengths and PAM4 technology, operating at a single-channel rate of 200 Gbps and necessitating two optical fibres, as depicted in the figure below. It sustains a transmission distance of 2km and is commonly employed in data centre interconnection, high-performance computing, storage networks, and other applications.

Finally, 800G FR8 utilises eight wavelengths, each operating at a speed of 100 Gbps, as illustrated in the figure below. It necessitates two optical fibres and supports a transmission distance of 2km. Additionally, 800G FR8 can offer increased transmission capacity. Typical applications include wide-area networking, data centre interconnection, and so forth.

Multimode 800G Transceivers

There are primarily two standards for 800G optical transceivers used in multimode applications when the transmission distance is under 100 meters.

800G SR8

The 800G SR8 transceiver adopts the VCSEL technology with a wavelength of 850nm and a single-channel rate of 100Gbps PAM4. It necessitates the use of 16 optical fibres. This can be regarded as an enhanced version of the 400G SR4, featuring twice the number of channels. The transceiver employs either an MPO16 or a Dual MPO-12 optical interface, as depicted in the diagram provided. OSFP 800G SR8 optical modules are generally used for 800G Ethernet, data centre links, or 800G-800G interconnection.
The FS OSFP 800G SR8 optical transceiver has a built-in Broadcom 7nm DSP chip with a maximum power consumption of 15W, providing high speed and low power consumption in 800G links. The top-fin OSFP is used in Quantum-2 air-cooled switches and is suitable for use in InfiniBand NDR end-to-end systems. It is also perfectly compatible with NVIDIA QM9700/9790 devices for seamless integration into compute and storage infrastructures, ensuring efficient high-performance interconnections.

800G SR4.2

This scheme utilises two wavelengths, 850nm and 910nm, enabling bidirectional transmission over a single fibre, commonly referred to as bi-directional transmission. The module incorporates a DeMux component to separate the two wavelengths. With a single-channel rate of 100 Gbps PAM4, it requires a total of 8 optical fibres, which is half the amount needed for SR8.

Applications of 800G Transceiver

In the realm of high-performance networking, the evolution of 800G transceivers has ushered in a new era of possibilities.

Data Centre Connectivity

Data Centre Interconnectivity is one of the primary domains where the prowess of 800G optical modules shines. With InfiniBand, these modules facilitate seamless communication between data centres, powering the backbone of modern interconnected infrastructures.

High-Performance Computing

In the arena of High-Performance Computing, where processing demands are ceaselessly escalating, the efficiency of 800G transceives becomes a game-changer. Modules ensure fast data transfer, reduce latency, and optimize overall system performance.

5G and Communication Networks

The proliferation of 5G and communication networks demands not only speed but also reliability. Enter 800G QSFP and QSFP-DD transceivers, engineered to meet the needs of next-generation communication networks. Their advanced capabilities underpin the 5G architecture, ensuring a robust and responsive network infrastructure.


As a key component of next-generation high-speed optical communications, 800G optical modules are available in a variety of types to fulfil diverse application requirements. A comprehensive understanding of the types of transceivers, application areas, and answers to common questions about 800G transceivers will facilitate the advancement of data transmission technology. By mastering this advanced technology, we can more effectively adapt to the challenges and opportunities of the digital age.

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What Is 800G OSFP Optical Transceiver?

OSFP is a new form factor with 8 high-speed electrical lanes. Currently, OSFP modules support speeds of 200G, 400G, and 800G. It is an advanced high-speed transceiver module that utilizes fibre optic technology to transmit and receive data at astonishing speeds. Particularly, the 800G OSFP version offers eight times the bandwidth capacity of traditional 100G modules. Its compact design allows for denser port configurations on network equipment, ensuring more efficient use of space.

Why Choose 800G OSFP Optical Transceivers?

The 800G OSFP transceiver epitomizes advanced optical technology, delivering unparalleled network performance through high-speed data transmission. Here are the advantages of the 800G OSFP optical transceivers:

High-Speed Data Transmission: The OSFP transceiver ensures fast data transfer at 800G, mitigating network latency and effectively supporting latency-sensitive applications.

High-Density Configuration: The 800G OSFP boasts a compact design that allows for high-density port configurations on networking devices. This enhances spatial efficiency and facilitates increased capacity connectivity in data centres.

Robust Durability: Engineered for resilience, the 800G OSFP Transceiver features a sturdy construction capable of enduring continuous high-speed data transmission. This guarantees longevity and resilience in demanding network environments.

Power Efficiency: With its embedded Broadcom DSP chip, the 800G OSFP transceiver provides high-speed, stable transmission in 800G links while minimising power consumption. This facilitates the construction of more environmentally friendly and sustainable network infrastructures.

Future Outlook: The 800G OSFP transceiver is designed for the future, aiming to support next-generation network standards and technologies. This makes it a wise investment, ensuring your network is equipped to handle future technological advancements.

Application Scenarios of 800G OSFP Optical Transceivers

  1. Data Centres: With the ability to facilitate dense port configurations and efficient high-volume data processing, 800G OSFP transceivers are proving indispensable in data centre environments.
  2. Telecommunications: Telecom companies can capitalize on the exceptional speed and bandwidth capabilities offered by the 800G OSFP Transceiver to optimize network performance and meet the requirements for high-speed connectivity.
  3. Cloud Service Providers: The 800G OSFP Transceiver supports the seamless operation of cloud services, enabling cloud service providers to deliver high-speed, reliable services to their clients.
  4. Machine Learning and AI: Given their powerful bandwidth and speed capabilities, 800G OSFP transceivers are indispensable for enterprises looking to harness the potential of machine learning and artificial intelligence technologies.
  5. Internet Service Providers (ISPs): ISPs can harness the power of the 800G OSFP Transceiver to enhance their network infrastructure, elevate customer service standards, and adeptly manage surging data traffic demands.
  6. Digital Broadcasting: In digital broadcasting, seamless delivery of high-quality services hinges on the 800G OSFP Transceiver’s adeptness at facilitating swift and uninterrupted high-speed data transmission.
TypeProductMax Cable DistanceConnectorWavelengthOptical Modulation
EthernetOSFP-2FR4-800G2kmDual LC Duplex1310nm100G PAM4
EthernetOSFP-DR8-800G500mDual MTP/MPO-121310nm100G PAM4
EthernetOSFP800-PLR8-B110kmMTP/MPO-161310nm100G PAM4
EthernetOSFP800-PLR8-B210kmDual MTP/MPO-121310nm100G PAM4
EthernetOSFP800-2LR4-A210kmDual LC Duplex1310nm100G PAM4
EthernetOSFP-SR8-800G50mDual MTP/MPO-12850nm100G PAM4
InfiniBandOSFP-SR8-800G50mDual MTP/MPO-12850nm100G PAM4
InfiniBandOSFP-DR8-800G500mDual MTP/MPO-121310nm100G PAM4
InfiniBandOSFP-2FR4-800G2kmDual LC Duplex1310nm100G PAM4

Ethernet OSFP VS InfiniBand OSFP

Both Ethernet OSFP and InfiniBand OSFP are high-speed optical modules designed for different network environments and applications, but they differ in terms of protocol, applications, and standard adherence.

Ethernet OSFP

Primary Applications: Primarily used for high-speed network transmission in data centres and enterprise networks, supporting various speeds such as 40G, 100G and 400G, it is suitable for large-scale data transmission and high-speed interconnection.Distance and Medium: Can connect distant devices through optical fibre, suitable for large-scale network layouts.Interoperability: Good compatibility with existing network equipment and standards, easy integration into complex and dynamic network environments.Protocol Support: Mainly supports Ethernet protocols and is tightly integrated with the IP protocol stack, suitable for regular data centre network requirements.

InfiniBand OSFP

Primary Application: Mainly used in high-performance computing (HPC), artificial intelligence (AI), and machine learning (ML) applications with extremely high-performance requirements.Performance: InfiniBand offers extremely low latency and high data transfer rates, typically better suited to environments with extremely high-performance requirements than traditional Ethernet.Interoperability: Typically used in specific, highly optimised environments. While its versatility is not as high as Ethernet, it offers unparalleled performance advantages in particular environments.Protocols and Architectures: Unlike traditional networks, protocols and architectures are designed for efficient data transmission and low-latency communication.
The choice between Ethernet OSFP and InfiniBand OSFP will depend on your specific application requirements and network objectives. Ethernet OSFP is a better choice if your application primarily focuses on traditional data centres, cloud computing, or large-scale network environments, and requires compatibility with multiple network devices and standards. However, if your environment requires extremely high data processing capabilities and the lowest possible latency, such as in HPC or AI computing, then InfiniBand OSFP would be more suitable.


In conclusion, the 800G OSFP module stands as a groundbreaking advancement in high-speed networking technology. With its remarkable bandwidth capacity, compact design, and versatile applications, it is poised to revolutionize data transmission in various industries. Embrace the future of connectivity with the 800G OSFP module and stay ahead in the ever-evolving digital landscape. From cutting-edge R&D to global warehouses, we offer effective solutions tailored to your needs. Seize the opportunity – Sign up now for enhanced connectivity or apply for a personalised high-speed solution design consultation. Transform your network with FS today.

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Evolution of 800G OSFP Optical Modules Unveils the Future

Within the ever-evolving realm of high-speed networking, the progression of 800G OSFP optical transceivers emerges as a testament to innovation and advancement. From its inception to its current state, the evolution of 800G OSFP modules demonstrates the steadfast pursuit of swifter data transmission, expanded bandwidth, and improved performance within contemporary data centre environments. This article mainly shows the evolution route of 800G OSFP optical transceivers.

800G OSFP Optical Transceiver Evolution Route

Route 1: EML Route

The 800G DR8 OSFP optical transceiver integrates eight 100G EML lasers, representing a mature solution with robust performance. However, due to the high number of lasers, it incurs relatively higher costs. Looking ahead, advancements are anticipated to enable the realization of 800G DR4 OSFP, halving the laser count and consequently reducing costs. Long-term projections foresee the possibility of pricing approaching that of 400G optical modules.

The 800G DR8 OSFP optical transceiver, which integrates eight 100G EML lasers, represents a mature solution with robust performance. However, it incurs relatively higher costs due to the high number of lasers. Looking ahead, advances are anticipated to enable the implementation of 800G DR4 OSFP, halving the laser count and consequently reducing the cost. Long-term projections foresee the possibility of pricing close to that of 400G optical modules.

Route 2: Silicon Photonics Route

At present, 800G silicon photonics utilizes a dual-laser drive method, leveraging the existing 400G DR4 solution for cost efficiency compared to EML alternatives. Looking forward, advancements will drive a transition to a single-laser driving approach, integrating a thin-film lithium niobate modulator to minimize optical path loss. The single-laser solution in silicon photonics is set for mass production by 2025, offering further cost reductions for the 800G DR8 silicon optical module. Nonetheless, the dual-laser approach continues to dominate the mainstream for silicon photonics.

800G 2xFR4 OSFP Evolution Route

The current 800G 2xFR4 OSFP configuration utilises two sets of 4-wavelength CWDM 100G EML lasers, each consisting of 4 lasers. However, future advancements will transition towards an FR4 setup employing 4 CWDM wavelength 200G EML lasers.

This shift to 800G FR4 necessitates using 4-wavelength CWDM lasers in silicon photonics solutions, eliminating any cost advantage. Currently, the dominant preference lies with EML schemes, with no ongoing exploration of silicon photonics schemes by manufacturers. The FS 800G 2xFR4 OSFP transceiver features cutting-edge features such as a self-developed 53G EML laser chip and a built-in Broadcom 7nm DSP chip, ensuring unparalleled performance and reliability.

800G SR8 OSFP Evolution Route

Eight VCSEL lasers with a 50-meter transmission range are used in the 800G OSFP SR8 module. Due to the small distance, the application scenario is more constrained than the 400G SR8. We can observe that the shorter the transmission distance of a VCSEL laser, the larger its single-channel rate, by comparing the transmission distances of 10G, 25G, 50G, and 100G SR optical transceiver modules.

As the single-channel rate of optical modules increases, the VCSEL technology is reaching a bottleneck. Anticipating the era of 1.6T optical modules, VCSEL lasers may further limit the transmission distance. For cost-effective solutions, customers may find 1.6T cable options more favourable. As a result, the presence of VCSEL lasers in the 1.6T optical module market is expected to diminish in the future. The FS 800GBASE-SR8 OSFP optical transceiver is compliant with IEEE P802.3ck, OSFP MSA standard. Built-in digital diagnostic monitoring (DDM) allows access to real-time operating parameters. It is also suitable for 800G Ethernet, data centre and Breakout 2x 400G SR4 applications.

From CPO to LPO

CPO Solution

The CPO solution stands out in that it eliminates one DSP chip, thereby reducing power consumption and cost. It innovatively integrates the switching chip, which is responsible for the optoelectronic conversion, directly onto the optical module via co-encapsulation. This integration minimises electrical signal loss, reducing latency and overall power consumption. However, challenges arise regarding the co-packaging logistics and repair protocols for malfunctioning optoelectronic chip clusters, potentially delaying large-scale production and application for up to three years or remaining indefinitely in the conceptual phase.

LPO Solution

The LPO solution reduces power consumption by utilizing LPO linear direct drive technology and high linearity TIA and DRIVER chips. However, it compromises system error rate and transmission distance, rendering it suitable for specific applications. It depends on enhancements to switching chip performance and may potentially achieve transmission distances of up to 500m in the future, evolving into a viable solution for data centres.

Essentially, the LPO represents the evolutionary path of pluggable optical modules in terms of packaging. It provides a more straightforward and reliable alternative to the CPO solution.

Continuing the Exploration of 800G OSFP

Embarking on a journey through the evolution of 800G OSFP optical transceivers unveils a landscape shaped by innovation and technological prowess. As we navigate our way toward faster data transfer, expanded bandwidth, and improved performance, the diverse pathways showcased here underscore the dynamic nature of modern data centre environments. With each advancement, we edge closer to unlocking new possibilities and reshaping the future of high-speed networking. Continue to explore FS and embrace the transformative power of innovation.

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AI Computing Accelerates the Deployment of 800G Optical Transceiver

AI Computing Speeds Up Deployment of 800G Optical Transceiver

Demand for GPUs and other computing hardware has risen sharply in recent years as demand for AI computing continues to grow. In particular, the reliance on high-speed data transfer for AI training in data centres has driven an equally dramatic increase in the demand for AI server clusters and 800G optical module transceivers. As data centre infrastructure continues to expand, the use of optical modules has grown exponentially. At present, 200G and 400G transceivers have been deployed on a large scale, and 800G optical transceivers have begun to enter the mass production and introduction stage.

Why Do We Need 800G Optical Transceiver?

With the dramatic increase in global demand for data consumption and the associated technological advancements such as cloud computing, video streaming, AI and the global deployment of 5G networks, there is a growing need for high-speed data transmission in the marketplace. 800G optical transceivers have been created to provide the necessary bandwidth and speeds to efficiently handle the increased traffic and datasets, ensuring that technological development is not limited by data transmission rates. Market research firms forecast the 800G optical module market to grow at a CAGR of more than 25% over the next few years, reaching a market size of more than $5 billion by 2025.In addition, 800G optical transceivers meet industry requirements for scalability, flexibility and future readiness by improving energy and cost efficiency for data transmission. They allow networks to achieve higher bandwidth densities with fewer devices and connections while reducing power consumption per bit, helping data centre and telecom providers control operating costs while expanding network capacity and safeguarding the long-term value of investments.

Updating Data Centre Topology Architecture

Data centre network architectures are constantly evolving as data centre computing scales and east-west traffic continues to expand. In a traditional three-tier topology, data exchange between servers must go through access, aggregation, and core switches, which puts tremendous load pressure on the aggregation and core switches.

When further expanding the size of the server cluster with a conventional three-layer topology, the cost of the devices increases dramatically, as high-performance devices have to be deployed in the core and aggregation layers.

Instead, a two-layer Spine-Leaf topology is used to flatten the traditional three-layer architecture into two layers. In this setup, Leaf switches are similar to access layer switches in a traditional three-tier architecture, connecting directly to the servers. Spine switches, on the other hand, are equivalent to core layer switches and are directly connected to leaf switches, and each spine switch is connected to all leaf switches.

AI Computing and 800G Optical Transceivers
Compared to the traditional three-layer topology architecture, the spine-leaf architecture requires a significantly larger number of ports. Consequently, both servers and switches require more optical modules for fibre optic communication. For extensive AI training applications utilising GPUs, in NVIDIA’s DGX H100 servers, which integrate 8 H100 GPUs, the demand for compute and storage networking corresponds to approximately 12 800G optical transceivers and 18 400G optical transceivers. More information can be found in this post: Introduction to NVIDIA DGX H100.
This indicates that the number of high-speed optical modules required in data centres under leaf-spine architecture increases exponentially. As data centres scale up, especially with the demand for AI large model training, and the increased need for higher transmission rates in GPU servers, the adoption pace of 800G optical modules is accelerating.

Accelerated Deployment of FS 800G Optical Transceivers
Against the backdrop of AI computing advancement, the demand for 800G modules is steadily rising, with leading global manufacturers intensifying their deployment efforts. Interstellar Optics, for instance, has begun ramping up the production of its 800G optical modules in the first half of 2023, delivering steadily to key overseas clients alongside GPU-matched 800G products.
FS offers 800G optical transceivers of different transmission types, such as 800G QSFP-DD SR8, 800G OSFP SR8 and 800G OSFP 2xFR4, etc. Built-in Broadcom DSP chips, OSFP transceivers deliver high speed and low power consumption over 800G links, with a maximum fibre distance of up to 50m using 8 multimode fibres. Ideal for use in InfiniBand NDR end-to-end systems, FS 800G optical transceivers are an ideal solution for the supercomputing and AI industries, seamlessly integrating into computing and storage infrastructures to ensure efficient, high-performance interconnects.
And FS provides modules with two different protocols, InfiniBand and Ethernet. No matter what application scenario you face, our products can meet your needs. From high-speed data transmission to network expansion, FS’s 800G modules will provide you with excellent performance and reliability to help you achieve the success of digital transformation.
Center Wavelength850nm850nm1271nm, 1291nm, 1311nm and 1331nm
ConnectorMTP/MPO-16Dual MPO-12/APCDual LC Duplex
Cable Distance (Max.)30m@OM3/50m@OM430m@OM3
Modulation8×106.25G PAM48×106.25G PAM48×106.25G PAM4
Packaging TechnologyCOB (Chip on Board)
COB (Chip on Board) PackagingCOB (Chip on Board) Packaging
ChipBroadcom 7nm DSP ChipBroadcom 7nm DSPBroadcom 7nm DSP Chip
Power Consumption≤13W≤15W≤16.5W
Data Center
800G to 800G
800G to 2x400G Breakout
Data Center
800G to 2x400G


With the certainty of GPU orders driving demand, the mass shipment phase for 800G optical transceivers is set to commence in the latter half of this year. Serving as a vital link for AI computing power, the 800G optical transceivers are poised to witness accelerated market growth and deployment rates fueled by the expanding scale of data centres and the continuous rise in demand for AI training.

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Leveraging 25G CWDM Transceivers in 5G Fronthaul Networks

What is a 25G CWDM Transceiver?

The 25G CWDM transceiver plays a crucial role in modern telecommunications, particularly in 5G fronthaul networks. Operating at 25 Gbps, it utilizes CWDM technology to transmit multiple signals over one fibre, optimising bandwidth. Specifically designed for 5G fronthaul, it supports 25G Ethernet and CPRI/eCPRI, with impressive 10km link distances over single-mode fibre. Fully compliant with SFP28 MSA, CPRI, and eCPRI standards, it typically operates within the wavelengths of 1270nm-1370nm and 1470nm-1570nm.

If you want to know more about the differences between the 25G CWDM module and other 25G SFP28 modules, you can check out this article: 25G SFP28 Transceiver Module Overview.

 Figure 1: FS CWDM SFP28 Transceiver

What is the 5G Transport Network?

The 5G transport network encompasses fronthaul, midhaul, and backhaul, connecting cell sites with one another, then with the core network, and ultimately with data centres.


As 5G technology continues to evolve, the significance of “fronthaul” in the telecommunications industry is on the rise. This fiber-based link, integrated within the Radio Access Network (RAN) infrastructure, plays a pivotal role in achieving faster speeds and reduced latency. With the introduction of Distributed RAN (DRAN) and Centralized RAN (CRAN) approaches, base station components such as the Central Unit (CU), Distributed Unit (DU), and Active Antenna Unit (AAU) are undergoing substantial restructuring to meet evolving requirements. Fronthaul acts as the vital connection between the active antenna unit (AAU) and the distributed unit (DU), ensuring smooth communication and efficient data transmission. Innovations like the 25G CWDM SFP28 transceiver are essential for facilitating seamless communication and efficient data transfer across 5G fronthaul networks.


Midhaul is a vital element of the telecommunications network, acting as the intermediary between the fronthaul and backhaul segments. It encompasses the transmission path from the Distributed Unit (DU) to the Centralised Unit (CU). In the context of 5G networks, base stations are structured into a distributed architecture. Here, the DU oversees the transmission and reception of wireless signals, while the CU manages communication with the core network. Acting as a pivotal link between these two units, midhaul facilitates the transfer of data from the DU to the CU for further processing and dissemination across the network.


In addition to fronthaul and midhaul, the 5G transport network also includes the backhaul. This component consolidates access to traffic from the Radio Access Network (RAN) and utilises various technologies such as Ethernet, microwave, and optical fibre to transport it to the central office or data centre. The backhaul serves as a crucial link, connecting the fronthaul and midhaul to the core network, facilitating seamless data transmission across extensive distances.

Figure 2: 5G Transmission Networks Architecture

Utilisations of 25G CWDM Transceivers

In the initial stages of setting up 5G networks, fronthaul predominantly relies on direct fibre links, along with extensive coverage of both high-frequency and low-frequency spectrums for additional access points. To optimise the utilization of existing fibre resources, CWDM optical modules play a crucial role. The 25G CWDM solution allows for the selection of 6 or 12 wavelengths from the 18 specified in the ITU-T G.694.2 standard, spanning from 1271nm to 1611nm. Adhering to this standard enables optical transmission equipment from various vendors to operate harmoniously within the same network, ensuring network stability and reliability while mitigating issues stemming from equipment mismatches.

  • 25G CWDM SFP28 6-Wavelength Solution

The 6-wavelength 25G CWDM solution opts for the initial 6 shorter wavelengths (1271nm~1371nm) due to the maturity of the industry chain and the lesser impact of transmitter dispersion penalties (TDP). It’s widely agreed upon that the AAU side utilizes wavelengths of 1271nm, 1291nm, and 1311nm, while the DU side employs wavelengths of 1331nm, 1351nm, and 1371nm, as depicted in Fig.3. Additionally, the optical module on the AAU side requires cooled directly modulated lasers (DMLs) to meet industrial-grade standards.

Figure 3: 25G CWDM SFP28 6-Wavelength Solution
  • 25G CWDM SFP28 12-Wavelength Solution

The 12-wavelength 25G CWDM solution addresses a mixed transmission scenario involving both 4G and 5G networks. To enhance reliability and reduce component costs, the wavelengths ranging from 1271nm to 1371nm operate at a 25Gbit/s data rate for 5G fronthaul networks, while the wavelengths from 1471nm to 1571nm operate at a 10Gbit/s data rate for 4G fronthaul networks. This arrangement, illustrated in Fig. 4, facilitates the smooth transition from 4G to 5G base stations. However, in practice, the 25G SFP28 connector takes precedence due to its compatibility with both 4G and 5G networks, making the 12-wavelength solution less commonly used in real-world scenarios.

Figure 4: 25G CWDM SFP28 12-Wavelength Solution

Benefits of 25G CWDM Transceivers

  • Cost-effectiveness CWDM technology enables the transmission of multiple signal wavelengths over the same fibre optic cable, efficiently utilising fibre optic resources. With 25G CWDM optical modules, multiple data streams can be transmitted over a single fibre optic cable without the need for additional fibres, thus conserving fibre optic resources and reducing network construction costs.
  • Flexibility and Scalability Given the significant and ever-growing volumes of data typically associated with big data applications, networks must possess robust flexibility and scalability. By utilising 25G CWDM modules, users can dynamically select different wavelengths for data transmission, enhancing the adaptability and scalability of the network to meet the continuously expanding demands of big data processing.
  • Data Security In the realm of big data applications, the handling and processing of extensive volumes of sensitive data are routine, emphasising the critical importance of data security. 25G CWDM modules enhance data transmission security by segregating data streams of varying wavelengths into separate channels. This segregation reduces the risks of data leaks and interference, thereby enhancing the reliability and security of data transmission.


In brief, the 25G CWDM SFP28 is a critical optical transceiver that efficiently sends multiple signals down a single fibre optic cable using CWDM technology. It plays a pivotal role in providing effective data transmission solutions for 5G fronthaul networks. This technology not only optimizes how bandwidth is used but also meets the high-speed and low-latency demands of 5G networks. Moreover, it enhances data transmission security by segregating data streams into separate channels based on different wavelengths. Overall, its use ensures comprehensive protection for network performance, flexibility, and security, laying a solid foundation for the future of 5G communication.

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