Complete Guide to 25G SFP28 Optical Transceivers and Cables

Complete Guide to 25G SFP28 Optical Transceivers and Cables

The name of the 25G SFP28 comes from the fact that it is a Small Form-factor Pluggable (SFP) and its electrical interface can handle a channel of 25G, potentially up to 28G. The technology used in the SFP28 is the same as the 100G QSFP28.  Indeed, the “Quad” of QSFP28 takes its meaning from the fact that 100GBase QSFP28 provides four channels of 25G, potentially up to 28G.

Four Technologies

Four different technologies can be found among the 25GBase SFP28  family: Multi-mode TransceiversSingle-mode TransceiversDirect Attached Cables and Active Optical Cables. Of course, each technology has its advantages and inconveniences. In this article, we are going to introduce each technology to help you select the most suitable 25G SFP28 connectivity for your network.

Multi-mode Transceivers

Multi-mode transceivers are the low cost transceivers.  SFP28 SR use more expensive non-standard MPO connectors which cancel out some of the cost savings of the multi-mode transceiver.


The 25GBase SFP28 SR transceiver supports connections of up to 100 meters over multi-mode fiber and uses MPO connectors. The wavelength is 850nm. The short range (SR) transceiver is the most cost effective solution to upgrade to a 25G network.


Single-mode Transceivers

Single-Mode transceivers are more expensive than multi-mode transceivers but they allow to reach longer distance and most of them are using standard LC connectors. All single-mode 25G SFP28 transceivers are also available with industrial temperatures, ranging from -40°C to 80°C, which allows the transceivers to work in rougher environments with wide temperatures ranges.


The 25GBase SFP28 CWDM transceiver supports connections of up to 2km over single-mode fiber and uses standard LC connectors.


25G SFP28 LR

The 25GBase SFP28 LR  transceiver supports connections up to 10 km over single-mode fiber and uses standard LC connectors. The wavelength is 1310nm.

25G SFP28 LR

25G SFP28 Bidi

The 25GBase SFP28 Bidi transceiver supports connections up to 10km over single-mode fiber and uses LC connectors. The wavelengths are 1330TX/1270RX and1270TX/1330RX.

25G SFP28 Bidi

Direct Attached Cables (DAC)

Direct Attached Cables are a very common method used for very short-range distances because of the their low-cost. Indeed, they are the cheapest solution to connect 25G equipment. In addition, it is a one part product instead of the usually three part solution (two transceivers and a cable), which reduces the problems associated with dirty connectors. DAC also consume less power compared to Active Optical Cables (AOC).

There are two types of DAC, the passive copper cable for distance from 0 to 5 meters and active copper cable for distance from 5 to 15 meters.

25G SFP28 to SFP28 DAC

25G SFP28 to 25G SFP28 DAC

100G QSFP28 to 4 x 25G SFP28 fanout DAC

QSFP28 to 4 x 25G SFP28 fanout DAC

Active Optical Cables (AOC)

Active Optical Cables are comparable to using transceivers and separated cables. They can reach longer distance than DAC, up to 100 meters. They also are lighter and smaller than DAC.

25G SFP28 to SFP28 AOC

25G SFP28 to SFP28 AOC

100G QSFP28 to 4 x 25G SFP28 fanout AOC

QSFP28 to 4 x 25G SFP28 fanout AOC


Technology Standard Optech Part Number Features
Multi-Mode Transceivers 25G SFP28 SR OPAX-MX1-85-CB 850nm, MPO, 100 meters, 0~70°C
Single-Mode Transceivers 25G SFP28 CWDM OPAX-C08-yy-CB 1310nm, LC, 2km, 0~70°C
25G SFP28 CWDM IT OPAX-C08-yy-IB 1310nm, LC, 2km, -40~85°C
25G SFP28 LR OPAX-S10-13-CB 1310nm, LC, 10km, 0~70°C
25G SFP28 LR IT OPAX-S10-13-IB 1310nm, LC, 10km, -40~85°C
25G SFP28 Bidi OPAX-W10-xx-IB 1270/1310nm, LC, 10km, -40~85°C
Direct Attached Cables SFP28 to SFP28 DAC OPSF28-T-X5-PE xx= 0,5 to 5 meters
QSFP28 to 4 SFP28 DAC OPQS28-T-XX-P/SF28/4 xx= 0,5 to 5 meters
Active Optical Cables SFP28 to SFP28 AOC OPSF28-F-03-AKT xx= 1 to 100 meters
QSFP28 to 4 SFP28 AOC  OPQS28-F-01-A/SF28/4 xx= 1 to 100 meters

Optech products are compatible with all major switches and servers brands. You can check all the compatible lists here.

About Optech

Optech is a leading company in developing and manufacturing Optical Transceivers and Cables solutions for Data Center and Telecom market. Since 2001, Optech has been offering accurate lead time and high quality products to customers.

Optech offers a broad range of networking and communication solutions in following categories: Optical Transceivers, SFP, 10G SFP+, 25G SFP28, 40G QSFP+, 100G QSFP28 , Direct Attach Cables (DAC), Active Optical Cables (AOC), Ethernet Media Converter, Fiber Optical Patchcord, BWDM, CWDM, DWDM Mux/Demux and Repeater products.

For more information you can visit or contact us at

Others Complete Guide

Complete Guide to 10G Optical Transceivers

Complete Guide to 40G QSFP+ Optical Transceivers and Cables

Complete Guide to 100G QSFP28 Optical Transceivers and Cables

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