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25G SFP28 Transceivers Explained

In the realm of data communication, the pursuit of faster, more efficient transmission has always been paramount. As the demands of modern technology continue to escalate, the need for cutting-edge solutions becomes increasingly apparent. Enter the 25G transceiver – a groundbreaking innovation poised to redefine the landscape of data transmission.

Introduction to 25G Transceivers

At its core, a transceiver serves as the backbone of data communication, facilitating the exchange of information between devices. The emergence of 25G transceivers marks a significant advancement in this field, offering unparalleled speed and reliability. Unlike its predecessors, which typically operated at lower speeds such as 10G or 1G, the 25G transceiver boasts a transmission rate of 25 gigabits per second, representing a monumental leap forward in data transfer capabilities.

Advantages of 25G SFP28 Modules

Higher Bandwidth: 25G SFP28 transceivers provide higher bandwidth compared to their predecessors, such as 10G SFP+ transceivers, allowing for faster data transmission rates.

Backward Compatibility: Despite the higher data rates, SFP28 transceivers are often backward compatible with 10G SFP+ ports, enabling smooth migration paths for network upgrades without requiring immediate replacement of existing hardware.

Lower Power Consumption: SFP28 transceivers typically consume less power compared to QSFP28 transceivers, making them more energy-efficient and suitable for environments where power consumption is a concern.

Flexibility: SFP28 transceivers can support various networking protocols and applications, providing flexibility for different use cases.

Types of 25G SFP28 Transceivers

SFP28 SR Short-Reach (SR) Transceivers

Short-reach transceivers are designed for relatively close distances within a data center environment, typically spanning up to 100 meters over multimode fiber (MMF) cables. They are ideal for interconnecting switches, servers, and storage devices within the same rack or adjacent racks.

SFP28 Long-Reach (LR) Transceivers

Long-reach transceivers are optimized for longer distances, reaching up to 10 kilometers over single-mode fiber (SMF) cables. They are well-suited for interconnecting equipment across different areas of a data center or extending connectivity between geographically dispersed facilities.

SFP28 Extended-Reach (ER) Transceivers

Extended-reach transceivers offer intermediate reach capabilities, falling between short-reach and long-reach options. They typically support distances of up to 30 kilometers, making them suitable for applications requiring connectivity beyond the reach of standard short-reach transceivers but not as extensive as long-reach alternatives.

25G BiDi Transceivers

The 25G BiDi SFP28 transceiver module operates uniquely compared to standard 25G SFP28 transceivers. It facilitates both transmission and reception of signals over a single strand of fiber optic cable and requires usage in pairs. This module employs two optical signals with differing center wavelengths. For instance, one end may transmit at 1270nm and receive at 1330nm, while the other end transmits at 1330nm and receives at 1270nm. By enabling bidirectional transmission on a single fiber, BiDi SFP28 transceivers optimize fiber utilization, paving the way for the advancement of 5G communication technology.

25G WDM Transceivers

The 25G WDM SFP28 transceiver module encompasses three main variants: the 25G CWDM SFP28 transceiver, the 25G DWDM SFP28 transceiver, and the 25G LWDM SFP28 transceiver, all integral components in 5G front-haul networks.

The 25G CWDM SFP28 transceiver operates as a single-mode CWDM transceiver designed for duplex optical data communications within the CWDM wavelength range (1271~1331nm). Tailored for short-range communication needs, particularly in city and access networks, this solution effectively addresses the current challenges in 5G millimeter wave pre-transmission.

Designed specifically for 25G Ethernet and CPRI/eCPRI links over single-mode fiber (SMF), the 25G DWDM SFP28 transceiver optimizes bandwidth utilization by densely packing wavelengths together, enhancing network performance over existing fiber infrastructure.

The 25G LWDM SFP28 transceiver offers a cost-effective solution within the 25G WDM transceiver lineup, leveraging economical DML lasers for reliable transmission. This variant excels in 5G front-haul transmission scenarios, facilitating multi-channel signal transmission over a single fiber and thereby conserving valuable fiber resources.

FAQs about SFP28 Transceivers

Q: What is the maximum distance supported by 25G SFP28 transceivers?

A: Currently, the maximum supported distance for 25G is 40km, achievable with the SFP-25G-ER transceiver module. There’s potential for additional optics to be introduced in the future to extend supported distances further.

Q: Is it possible to utilize SFP28 transceivers in SFP+ ports?

A: Optical transceivers are designed to operate at specific speeds upon manufacture. Attempting to employ an SFP28 transceiver in an SFP+ port may result in link failure.

Q: Is it feasible to employ SFP+ transceivers in SFP28 ports?

A: Theoretically, yes, it’s possible. However, the link speed would be restricted to 10Gbps.


The 25GbE transceiver serves as a crucial component in the implementation of 25G Ethernet technology across cloud and enterprise data center environments. Acting as an advanced evolution from SFP+, the 25G SFP28 transceiver is capable of efficiently handling 25Gbps per lane, while also retaining compatibility with both SFP and SFP+ standards. This capability ensures seamless integration and optimal performance in diverse networking infrastructures, meeting the evolving demands of modern data center deployments.

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