Single fiber SFPs are always deployed in matched pairs, sometimes referred to as “A-end” and “B-end” modules. These paired modules use complementary wavelengths. For instance, if the local SFP transmits at 1310nm and receives at 1550nm, the remote SFP must transmit at 1550nm and. Single fiber module also called BiDi transceiver or WDM module. It uses WDM technology to realize the bidirectional transmission of optical signals on one optical fiber. Tx wavelength — one. Fiber optic cables are an essential component of modern telecommunications, providing high-speed data transmission capabilities over long distances.