A bi-directional WDM communication system of the type having central and local offices, and subscribers is provided. The central office includes downstream Bragg reflector lasers for generating downstream channels of different wavelengths, each channel being wavelength-locked to a corresponding incoherent light beam. The central office multiplexes the downstream channels into a downstream optical signal, demultiplexes an upstream optical signal into upstream channels of different wavelengths, and detects the upstream channels. The local office demultiplexes a downstream optical signal into downstream channels, multiplexes upstream channels of different wavelengths into an upstream optical signal, outputs it to the central office, and demultiplexes a broadband light beam into incoherent light beams of different wavelengths. Each subscriber receives the corresponding downstream channel and incoherent light beam, includes an upstream Bragg reflector laser for generating an upstream channel wavelength-locked to the received incoherent light beam, and outputs the upstream channel to the local office.