Common 40G QSFP+ multi-mode optical modules include SR4 and BIDI, so what is the difference between the two multi-mode optical modules? And how to choose it? Walsun will introduce these two optical modules to you. The package type of QSFP-40G-SR4 is QSFP+, the interface type is MPO, the transmission distance can reach up to 100 meters when used with OM3 patch cords; and the transmission distance can reach up to 150 meters when used with OM4 patch cords. QSFP-40G-SR4 can not only realize 40G transmission by connecting 8-core MPO-LC branch cables.
The package type of QSFP-40G-SR-BD is QSFP+, the interface type is LC, the transmission distance can reach up to 100 meters when used with OM3 patch cords; and the transmission distance can reach up to 150 meters when used with OM4 patch cords. QSFP-40G-SR-BD can use the multi-mode OM3 duplex LC patch cord in the 10G wiring system to quickly build a 40G network without adding a fiber adapter box.
Through the above introduction to these two optical modules, the difference between these two optical modules is already obvious (as shown in the table below), The QSFP-40G-SR4 optical module uses 4 10G parallel lines for transmission, so it not only compiles with IEEE 802.3ba 40GBASE-SR4 Ethernet standard, but also compatible with IEEE 802.3ae 10GBASE-SR Ethernet standard, and can be connected with 10G SR.
| Abbreviation | ETU PN | Different interface | Different Fiber Counts | Different working principles |
| QSFP-40G-SR4 | EQ854X-3MCD01 | MPO | 8-core | 4-way 10G parallel transmission |
| QSFP-40G-SR-BD | EQBxx4X-3LCD01 | LC | 2-core | 2-way 20G single-fiber bidirectional |
The QSFP-40G-SR-BD optical module adopts 2-way of 20G BIDI single-fiber and dual-fiber for transmission, it can use duplex LC multi-mode OM3 patch cord for transmission, and this kind of patch cord is a 10G multi-mode wiring scheme, so there is no need to change the existing 10G wiring pattern.The above is the introduction of two 40G multi-mode optical modules by Walsun, among them, the QSFP-40G-SR-BD optical module can realize the upgrade from 10G to 40G without changing the existing 10G wiring, while the QSFP-40G-SR4 optical module can be directly connected with the MPO-LC patch cord and the 10G SR optical module, therefore, it鈥檚 widely used in 10G to 40G network upgrade solutions. Through the introduction of this article, readers can choose an optical module that is most suitable for you according to the actual situation.
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