Single fiber QSFP28 modules (commonly called BiDi transceivers) enable full-duplex 100G communication over a single optical strand. They do this by using Wavelength Division Multiplexing (WDM) to carry upstream and downstream signals at different wavelengths on the same fiber. Tx wavelength — one. 1000BASE-SX SFP transceivers are specifically designed to work with multi-mode fiber (MMF) and operate near the 850 nm wavelength. These modules are also useful for intra-building links, such as. Gigabit single-mode fiber optic module Common parameters of optical modules 1. Center wavelength 1) 850nm (MM, multi-mode, low cost, but short transmission distance, usually only 500M); 2) 1310nm (SM, single mode, large loss during transmission, small dispersion, generally used for transmission. The 100GBASE-FR, based on the IEEE 802.