Optical fiber loopback (Lookback), also known as optical module self-loop test loop, is used to test the signal backhaul in the system or network system, and can detect various potential abnormalities in the network link by returning the signal (mainly connecting the transmitter of the TX to the receiving side of the RX in pairs). The optical signal in the optical fiber will reduce the optical power due to absorption, scattering and other reasons during the transmission process, and the optical fiber loss has an important impact on the communication distance.
Because optical fiber connectors are divided into LC, SC, FC, ST, MU, MT, MPO/MTP, etc., there are also very corresponding types of optical fiber loopers.