A bidirectional wavelength division multiplexed Passive Optical Network (PON) has been proposed in which downstream Differential Phase Shift Keying (DPSK) signal is used for upstream On Off Keying (OOK) signal demodulation. This proposed passive optical network architecture is capable to support the high bandwidth requirements for present applications such as video conferencing, online gaming, telemedicine etc. Due to use of wavelength division multiplexing, insertion losses of the proposed architecture are also reduced. Due to low insertion losses, PON can work with low input powers. In this architecture, authors use 10Gbps DPSK signal for 1.25, 2.5 and 5Gbps OOK signal demodulation. Error free operation is achieved for 20km fiber without any dispersion compensation with low power penalty for downstream and negligible for upstream.