Introduction of common 100G QSFP28 optical modules



100G has a variety of packaging forms, including CFP/CFP2/CFP4, CXP and QSFP28. Among these different 100G packaging forms, QSFP28 optical module has the advantages of high port density, low power consumption and low cost, so it has become the main packaging form of 100G network. Therefore, we will focus on four types of 100G QSFP28 optical modules today.

1.100GBASE-SR4 QSFP28 optical transceiver

The 100GBASE-SR4 QSFP28 optical module is a parallel 100G optical module. The QSFP28 full-duplex optical module provides four independent transmit and receive channels, each function can run 25Gbps at 100 meters on OM4 MMF. A total data rate is 100Gbps. When the 100GBASE-SR4 QSFP28 module transmits the signal at the transmitter, the electrical signal is converted into optical signal through the laser array, then parallel transmission on the banded multimode fiber. When reaching the receiving end, the photodetector array converts the parallel optical signal into the parallel electrical signal.

2.100GBASE-LR4 QSFP28 optical transceiver

The 100GBASE-LR4 QSFP28 optical module is generally used with the LC single mode patch cord, and the maximum transmission distance can reach 10km.The100GBASE-LR4 QSFP28 optical module converts the 4 channels 25Gbps electrical signal into 4 LAN WDM optical signals, and then reuses it as a single channel to achieve 100G optical transmission. At the receiving end, the module reuses 100G light input de-multiplexing into 4 LAN WDM optical signals and then converts it into 4 electrical channel signal output channel

3.100GBASE-CWDM4 QSFP28 optical transceiver

The transmission rate of QSFP28 CWDM4 optical module is 103.1Gbp, which is mainly used in the fields of computing, high frequency trade and so on. Its cost is obviously higher than QSFP28 PSM4 optical module. Through coarse wavelength division multiplexing (CWDM) technology, QSFP28 CWDM4 module multiplexed four wavelengths of 1270nm, 1290nm, 1310nm and 1330nm to a single mode fiber for transmission

4.100GBASE-PSM4 QSFP28 optical transceiver

The QSFP28 PSM4 module is a product of high speed and low power consumption, which is specially used for optical interconnection in data communication applications. It conforms to PSM4 MSA optical interface specification. It has hot pluggable QSFP form and built-in digital diagnostic function. There are 4 independent full duplex channels, and each channel can reach 25.78Gbps data rate. The QSFP28 PSM4 module is mainly used in 40G and 100G Ethernet. The high bandwidth module supports the 100GbE optical link through the single mode fiber.

The differences between the four 100G QSFP28 optical modules:

Optical module type


Optical fiber type

Transmission distance



Multimode OM4 fiber



Duplex LC

Single mode fiber



Duplex LC

single mode fiber




Banded single mode fiber (8 core)