The method of coherent detection utilize image rejection in the receiver to obtain better performance in demodulation of FSK downstream. We implement it in passive optical network and adopt re-modulation which modulalte ASK signal directly on FSK signal as upstream. The possibility of extending the system to WDM-PON condition is also discussed. By image rejection receiver, we get obvious performance improvement featuring BER. When in long haul situation, compared with band-pass filter, the image rejection receiver greatly improve the BER. Several detailed parameters in the receiver are varied in certain range to indicate their effect on the system performance. Results show that the image rejection receiver we propose is suitable for access network, especially for long-distance access network.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.