With the rapid development of 40G Ethernet, the 40G optical mode is becoming more and more popular. Now we usually use the 40G QSFP+ optical module. This optical module can be divided into three types. Do you know what are the difference between them? Let’s learn about it!

Three types of 40G QSFP+ optical modules: QSFP-40G-SR4, QSFP-40G-LR4 and 40G LR4 PSM.

QSFP-40G-SR4 module: Generally used with MPO/MTP connector, usually use multimode fiber link to achieve 40G transmission. When used with OM3 multimode fiber, the transmission distance is 100m, and the transmission distance is 150m when used with OM4 multimode fiber.

QSFP-40G-LR4 module: It is generally connected to the LC duplex connector, the maximum transmission distance is 10km.

40G LR4 PSM module: It is also used with the MTP/MPO connector, using MPO/MTP interface of the 4 - way parallel design, used with single mode fiber, the transmission distance is 10km.

Comparison of QSFP-40G-SR4 module and QSFP-40G-LR4 module

Form above, we can see that their connector is different. In addition, the QSFP-40G-SR4 module is often used multimode fiber for transmission, and the transmission distance is short. QSFP-40G-LR4 module is often used single mode fiber for transmission, and the distance of transmission is much farther. Below is their working principles.

Comparison of 40G LR4 PSM module with QSFP-40G-SR4 module and QSFP-40G-LR4 module

Compared with QSFP-40G-SR4 module: Working principle is same, convert the photoelectric signal through the laser array. 40G LR4 PSM module is suitable for long-distance transmission, and the QSFP-40G-SR4 module is for short-distance transmission.

Compared with QSFP-40G-LR4 module: Although they are suitable for long-distance transmission, 40G LR4 PSM module requires 8 single mode optical fibers for transmission, and QSFP-40G-LR4 module only needs 2 single mode optical fibers for transmission.

We hope that through this article, can help you have a deeper understanding of these three 40G QSFP+ optical transceivers. We believe that this can also help you better judge what kind of light modules are used in any case. ETU-Link can provide customers with a series of cost-effective 40G QSFP+ solutions to meet different wiring needs. For more details, welcome to visit our website: www.etulinktechnology.com