The QSFP+ optical module, the 40G optical module, is a compact optical module for data communication applications. It has four independent optical signal transmission and reception channels, which are mainly used for high-speed data transmission of switches, routers and data center equipment. The 100G QSFP 28 optical module of Road Communication includes SR4, CWDM4, LR4 series.
Classification of QSFP+ optical modules
There are currently four types of QSFP+ optical modules commonly available on the market:
1.40G LR4 QSFP+ Optical Module
40G LR4 QSFP+ optical module, generally used with LC single-mode fiber jumper, with a maximum transmission distance of 10km, high density, low cost, high speed, large capacity, low power consumption, and it has four data channels. Can transmit data at the same time.
The working principle of the 40G LR4 QSFP+ optical module: the laser driver controls the arriving wavelength, and the optical signal is then passed through the multiplexer to combine them for transmission. Near the receiving end, these transmitted signals are decomposed into four channels with a transmission rate of 10 Gbps, and then the PIN detector or transimpedance amplifier recovers the data stream and then transmits the optical signal.
2.40G SR4 QSFP+ Optical Module
The 40G SR4 QSFP+ optical module operates at 850nm. It uses four independent full-duplex channels for data transmission. The transmission rate is the same as that of the 40G LR4 
QSFP+ optical module. The difference is that it is often used with multimode fiber. Generally, the MPO/MTP connector has a transmission distance of 100 m when used with the OM3 fiber patch cord and 150 m when used with the OM4 fiber patch cord.
40G SR4 QSFP+ optical module works: When the signal is transmitted at the transmitting end, the electrical signal is first converted into an optical signal by the laser array. When the transmitting end transmits the signal and the receiving end receives the signal, the photo detector array converts the parallel optical signal into parallel. electric signal.
3.40G LR4 PSM QSFP+ Optical Module
The 40G LR4 PSM optical module is a highly integrated 4-channel optical module that uses parallel single-mode technology, PSM, with 4 channels in parallel. Its transmission distance is 10km. The connector is generally an MPO/MTP connector. The port density is high and the cost is low.
The 40G LR4 PSM optical module works in the same way as the 40G SR4 QSFP+ optical module. The difference is that 40G LR4 PSM optical modules are often used to connect to single-mode ribbon fiber connectors, that is, parallel optical signals are transmitted in parallel through eight single-mode fibers.
4.40G ER4 QSFP+ Optical Module
The 40G ER4 QSFP+ optical module converts four 10G data input channels into four CWDM optical signal channels at 11.2Gbps and then multiplexes them into a single channel for 40G data transmission. The connector is typically LC duplex.
