Patent ID: 7271949

Claim:
A wavelength division multiplexing system including a central office configured to generate downstream optical signals, a plurality of subscriber units configured to receive corresponding downstream optical signals, and a remote node configured to connect the central office to the subscriber units, the central office comprising a multi-wavelength light source, a multiplexer/demultiplexer, and a plurality of semiconductor light sources, the multi-wavelength light source including an amplifier and an optical fiber, the amplifier configured to generate light over a predetermined wavelength range, the optical fiber grating configured to divide the light into a plurality of downstream channels having different wavelengths to reflect the downstream channels to the amplifier, the multiplexer/demultiplexer is configured to demultiplex the downstream channels generated in the multi-wavelength light source according to respective wavelengths, the semiconductor light sources are configured to generate downstream optical signals mode-locked by corresponding downstream channels from among the downstream channels multiplexed by the multiplexer/demultiplexer, wherein the multiplexer/demultiplexer is configured to multiplex the downstream optical signals inputted from the semiconductor light sources to output the multiplexed optical signal to the remote node.