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Unveiling The Product Feature and Application of 100G QSFP28 Multimode Optical Transceiver Modules

The rapid growth of data center requirements and the rollout of 5G networks, led to a surge in demand for 100G transceiver modules. These modules represent a substantial portion of the total network construction expenses. In the confined spaces of data centers, especially in small to medium-sized facilities, most fiber links span distances of less than 100 meters. Even in larger data centers, more than 70% of fiber links are under 100 meters, with over 80% falling short of 125 meters.


In response to these prevalent short-distance requirements, multimode fiber has become the preferred solution for most data center links. This has led to the 100G multimode module emerging as the most sought-after option. Among the variety of solutions available, the QSFP28 100G multimode module distinguishes itself with its versatility. Critical contenders in this category include the 100GBASE-SR4, 100GBASE-SR BD, 100GBASE-SWDM4, and 100G QSFP28 BiDi SR1.2. Each option offers distinct advantages tailored to specific networking needs, enabling data centers to optimize their infrastructure to meet evolving demands while effectively managing costs.


The Different Types of 100G QSFP28 Multimode Transceiver Modules Introduction


100G QSFP28 SR4


The 100G QSFP28 SR4 module is precisely engineered to facilitate high-speed, short-range data transmission utilizing multimode fiber. Operating at a wavelength of 850nm, up to 100 meters, it is well-suited for intra-data center connections. With its four parallel lanes, the QSFP28 SR4 module can achieve an impressive data rate of 100 Gbps, ideal for handling substantial volumes of data in data centers and enterprise networking environments. Its design emphasizes efficiency and reliability, meeting the demands of modern networking applications where high bandwidth and low-latency connectivity are essential requirements.



The 100GBASE-SR BD module presents a cost-effective solution tailored for short-range data transmission within data center environments. They are utilizing a bidirectional (BiDi) transmission scheme. Operating at a wavelength of 850nm, the 100GBASE-SR BD module supports transmission distances of up to 100 meters over OM4 multimode fiber, making it suitable for efficiently connecting equipment within data centers while minimizing infrastructure costs. This approach underscores the module’s practicality in addressing the evolving needs of data center networks, where maximizing efficiency and minimizing operational overheads are paramount concerns.



The 100GBASE-SWDM4 module harnesses Short Wavelength Division Multiplexing (SWDM) technology to deliver efficient high-speed data transmission over duplex multimode fiber. By leveraging four distinct wavelengths within the 850nm spectral window, this module can achieve transmission distances of up to 150 meters over OM4 fiber, expanding connectivity capabilities within data center environments. Notably, the 100GBASE-SWDM4 module offers a cost-effective means of enhancing existing multimode infrastructure to support higher data rates, presenting an attractive solution for organizations seeking to optimize their network performance without requiring a complete overhaul of their fiber infrastructure. This approach underscores the module’s adaptability and value in meeting the evolving demands of modern data center networks, where maximizing efficiency and minimizing costs are key priorities.

100G QSFP28 BiDi SR1.2


The 100G QSFP28 BiDi SR1.2 module presents a streamlined and effective solution tailored for short-range data transmission within the data center and campus networking environments. This module significantly reduces fiber cabling needs and simplifies installation processes, optimizing network efficiency by leveraging bidirectional transmission over a single fiber pair. Enhanced by the SR1.2 standard, the module supports transmission distances of up to 70 meters over OM3 multimode fiber, making it particularly suitable for high-density deployment scenarios where space optimization is crucial. 100G QSFP28 BiDi SR1.2 module highlights its versatility and value in addressing the evolving connectivity requirements of modern networking infrastructures, emphasizing efficiency and performance in demanding operational environments.


The Application of 100G QSFP28 Multimode Modules


100G QSFP28 SR4


The 100GBASE-SR4 is a highly favored 100G multimode module known for its widespread adoption. This 100G QSFP28 SR4 module represents a cutting-edge, hot-pluggable, full-duplex optical solution with a center wavelength of 850nm and strict adherence to IEEE 802.3BA standards. Its primary application is facilitating short-distance transmissions within the domain of 100G Ethernet networks. Notably, the 100G QSFP28 SR4 optical module boasts four independent transmit and receive channels, each operating at an impressive rate of 25Gbps. By leveraging MPO or MTP interfaces containing eight cores, this module demonstrates remarkable transmission capabilities, supporting distances of up to 70m with OM3 multimode fiber and extending to 100m with OM4 multimode fiber. This module’s advanced design enables efficiency and reliability for data center and enterprise networking environments where performance and versatility are paramount.




The 100G QSFP28 SR BiDi (Bidirectional) module presents a unique and innovative approach compared to its SR4 counterpart, leveraging Wavelength Division Multiplexing (WDM) technology. This module enables each LC port to transmit and receive optical signals of distinct wavelengths over a single multimode fiber. This design allows for a total transmission capacity of 100G across the two LC interfaces. Operating on a dual-wavelength VCSEL bi-directional optical interface, these modules excel in PAM4 2 × 50-Gb/s transmission using 850nm and 900nm wavelengths. Their versatility is highlighted by their seamless integration with multimode fiber systems, supporting transmissions of up to 70 meters with OM3 fiber patch cables, up to 100 meters with OM4 fiber patch cables, and extending up to an impressive 150 meters with OM5 fiber patch cables. The operational principle of these modules emphasizes their effectiveness in optimizing network performance and ensuring smooth data transmission across diverse networking environments, making them well-suited for high-density data centers and enterprise applications.




The 100GBASE-SWDM4 module shares similarities with the 100G QSFP28 SR BiDi module, particularly in their use of duplex LC interfaces. SWDM, short for short-wave wavelength division multiplexing, aligns with concepts like CWDM4 and LWDM4 but in multimode configurations. Using MUX/DMUX technology, SWDM4 simultaneously transmits optical signals across four distinct wavelength bands over a single multimode fiber core. These wavelengths—850nm, 880nm, 910nm, and 940nm—enhance data transmission capabilities significantly. Notably, the 100GBASE-SWDM4 module showcases impressive transmission distances, supporting up to 70 meters with OM3 fiber patch cables and extending to 100 meters with OM4 fiber patch cables. This technology represents a sophisticated solution for high-speed data transmission within data centers, leveraging the efficiency of multimode fiber while maximizing performance and reliability.


100G QSFP28 BiDi SR1.2


As AI and machine learning workloads intensify, data centers face escalating computing and traffic demands. This surge necessitates denser and faster connections within data center architectures, particularly along ridges, backbones, and between ridge/rack top switches and servers. However, conventional upgrades from 10G to 40G or 100G often require converting LC duplex cabling used with SFP optical modules to MPO cabling for QSFP optical modules, leading to increased operational costs. Simplifying wiring and reducing capital expenditure becomes critical in such contexts. Here, the 100G QSFP28 BiDi SR1.2 optical module offers a solution, employing BiDi technology to address these challenges effectively.


Like its predecessor, the 40G QSFP+ SR BiDi module, the 100G QSFP28 BiDi SR1.2 enables data center operators to make use of their existing duplex LC jumper infrastructure when upgrading from 10G SR or 40Gb BiDi to 100G. This smooth transition process allows carriers to incrementally enhance their data center networks by upgrading individual network devices as needed.


The 100G QSFP28 BiDi SR1.2 is a Quad Small Form-factor Pluggable (QSFP28) BiDi optical module designed to support 100Gbps data transmission by the IEEE802.3bm 100GBASE-SR4 standard. Utilizing dual-core duplex LC multimode optical fiber, the module employs 4×25G NRZ modulation at the electrical end, seamlessly converting to 2x50Gbps PAM4 modulation at the optical end, achieving a total bandwidth 100Gb. PAM4 technology enables efficient signal transmission at both 50Gb data rates and 25Gbaud rates, ensuring optimal performance and efficiency in demanding data center environments.

The 100G QSFP28 SR BiDi modules are deployed in pairs to establish 100G connectivity. They can connect with the 400G QSFP+ SR BiDi in a 4 x 100G branch mode configuration.

While all four modules utilize multimode optical fibers, they employ different technical approaches. The 100G QSFP28 SR4 module uses a four-channel parallel transmission method, necessitating eight optical fibers for complete transmission (four for receiving and four for transmitting). Conversely, the 100GBASE-SR BD module uses a single optical fiber for bidirectional 50G data transmission, allowing both interfaces to transmit 100G data collectively. Similarly, the 100GBASE-SWDM4 module utilizes wavelength-division multiplexing (WDM) to combine signals from four distinct bands into a single optical fiber, requiring two fibers for efficient data transmission.


All modules are compatible with the widely used 100G QSFP28 port, ensuring easy integration into existing networking infrastructures. Despite significant differences in technical specifications, their applications exhibit minimal disparity. Regarding fiber resources and cabling costs, the 100GBASE-SR BD and 100GBASE-SWDM4 modules offer advantages, requiring only a quarter of the fiber resources compared to the 100GBASE-SR4 module. This efficiency leads to significant savings in capital expenditure for fiber infrastructure. However, it’s essential to consider that the upfront costs of the 100GBASE-SR BD, 100G QSFP28 BiDi SR1.2, and 100GBASE-SWDM4 modules are higher than those of the 100GBASE-SR4 module. Therefore, selecting the appropriate product based on actual program needs, considering both the optical module and fiber infrastructure costs is recommended.




6COMGIGA provides a comprehensive solution for short-distance connections within data centers. Our 6COMGIGA product line includes options like the 100G QSFP28 SR4, 100G QSFP28 BiDi SR1.2, and 100G QSFP28 SWDM4, all designed to integrate with duplex LC multimode fiber seamlessly. This versatility extends to replacing conventional optical modules like the 100G QSFP28 SR4, leading to significant savings in optical fiber resources and streamlining fiber management within the data center environment.

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