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

25G SFP28 ER

The 25G SFP28 ER supports connections of up to 40km over singlemode fiber and uses Duplex LC connector. The wavelengths is 1310nm.

25G SFP28 ER

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
25G SFP28 ER OPAX-S40-13-CB 1310nm, LC, 40km, 0~70°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.

You can find more information about 25G SFP28 Transceivers and Cables compatible brands in this article: 25G SFP28 Compatibility Matrix – Switch and NIC Card Brands

About Optech

Optech Technology Co. Ltd was founded in 2001 in Taipei, Taiwan. The company was created with a sole purpose, to provide a wide and high quality portfolio of optical products to a very demanding and fast evolving market.

To respond to the permanent increase of IP traffic, Optech portfolio is constantly growing. Since the beginning, the company has always been up to date with the latest innovations on the market. Today, we are proud to deliver a large selection of 25G SFP28, 40G QSFP+, 100G QSFP28 and 400G QSFP-DD optical transceivers and cables.

Optech has a large portfolio of products which include optical transceiversdirect attach cablesactive optical cablesloopback transceiversmedia converters and fiber patch cords.

Through its large selection of optical products, that have a range of data speed from 155 Mbps to 400 Gbps and reach distances up to 120km, Optech products are suitable for various industries such as telecom, data centers as well as public and private networks.

Optech also has a strong experience as an OEM supplier. We put our expertise and knowledge at the service of your brand.

To ensure the quality and the compatibility of our products, every product is carefully tested before delivery to our customers. In addition, Optech obtained several certifications such as UL, TUV Rheinland, ISO9001 and ISO14001 certification. All our optical transceivers are MSA and RoHS compliant.

At Optech, we value each and every customer. We know every demand is unique. For this reason, our team of experts is glad to answer all our customers’ specific demands.

Just like data, Optech has no boundaries and will optimize your network all over the world.

For more information you can visit or contact us at

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