We demonstrate a bidirectional long-reach 64-channel dense wavelength division multiplexing passive optical network (DWM-PON) based on wavelength-locked Fabry-Wrot laser diodes (F-P LDs) with 50-GHz channel spacing. The mode control of the F-P LDs enhances the output power and decreases the required injection power. Packet-loss-free transmission in both 64 upstream and 64 downstream channels is obtained, guaranteeing more than 100 Mb/s per channel through 70 km of single mode fiber without the need for an optical amplifier. The demonstrated DWDM-PON can consolidate a metro network into an access network by by assing the central offices within its reach. The. p capacity of the long-reach DWDM-PON is also discussed.