MPO fibers are used for 40G short reach (40G-SR) optical modules. An MPO fiber consists of multiple multi-mode fiber strands, and each multi-mode fiber strand provides one laser transmission channel. A 40G-SR optical module uses four channels to transmit laser and four channels to receive laser. That is, a total of eight channels are required for a 40G-SR optical module. According to optical fiber standards, each MPO connector provides 12 fiber strands.
Some fiber suppliers produce 12-strand MPO optical fibers, while some suppliers produce 8-strand MPO fibers. The two types of fibers use the same definition of fiber channels. Therefore, they are equivalent in functionality when connecting to 40G-SR optical modules.
