The wavelength-division multiplexing passive optical network (WDM-PON) is considered to be a promising method to
overlay or upgrade the existing optical access network. A centralized WDM-PON in which the downstream wavelength
is reused to modulate the upstream has been studied comprehensively, for same wavelength operation of both
downstream and upstream, colorless operation and source-free of optical network units (ONU) can be realized in such
systems. We propose a scheme of centralized WDM-PON with non-return-to-zero/continuous-wave (NRZ/CW)
polarization multiplexed downstream and remodulated upstream using a CW injection-locked Fabry-Perot (FP) laser.
This scheme can eliminate the crosstalk of downstream data on the upstream and get higher extinction ratio of received
downstream signal. Experiment with 22.2km transmission of 10-Gb/s downstream signal and 622-Mb/s upstream signal
was realized using a commercial FP laser, with power penalties of 0.2dB and 0dB respectively. 2.5-Gb/s upstream signal
using an injection locked FP laser was also investigated, and 61 modes within 25.4nm span were locked with side-mode
suppression ratio of above 27dB.