We propose the single feeder fiber architecture for wavelength division multiplexing passive optical network (WDM-PON) based on directly modulated chirp managed laser (CML). The downlink (DL) signal output from the laser is converted to return-to-zero (RZ) differential phase shift signal using a pulse carver. The downstream signal is reused as a carrier for the upstream using intensity modulation technique. Simulation results show the error-free performance at symmetric data rate of 10 Gbit/s per channel with negligible power penalty and improved receiver sensitivity for the uplink (UL), over 25 km standard single-mode fiber (SSMF). A low-cost and reduced circuitry network design is implemented on a single feeder fiber with the elimination of differential encoder and one external modulator.