Bi-directional transmission experiments using injection-locked FP-LD transmitters for WDM-PON

This paper describes bi-directional transmission experiments, 10 Gbit/s downstream and 2.5 Gbit/s upstream, using 10 km single-mode fibers (SMF) for wavelength division multiplex passive optical network (WDM-PON) applications. An optical transmitter at an optical network unit (ONU) uses a Fabry-Perot laser diode (FP-LD) injection-locked by intensity modulated downstream signal light. An extinction ratio (Ex) of downstream signal light is very important for both sending and receiving properties and the Ex influences the bit error rate (BER) property. There is a trade-off of power penalties for receiving up- and downstream signals and we confirmed it experimentally for the first time. We also discuss an optical amplification for an injection locking.