10G Bidi (Bi-Directional) transceiver modules operate on a single strand of SMF. The communication over a single strand of fiber is achieved by separating the transmission wavelength of the two devices. For 10km, 20km, 40km and 60km wavelength is 1270nm/1330nm. 80km is 1490nm/1550nm. Single fiber saves fiber resources compare with dual fiber one. Good cost performance, high reliability which suitable for data center, metro network and service provider transmission applications.