Optical wavelength multiplexer/demultiplexer

Claim 1

An optical wavelength multiplexer/demultiplexer incorporated in a substrate, comprising: at least one input channel waveguide for receiving wavelength-division multiplexed signals, said wavelength division multiplexed signals comprising a plurality of signals having a predetermined wavelength difference from each other; an input slab waveguide for expanding said wavelength division multiplexed signals coupled from said input channel waveguide into said input slab waveguide; an arrayed-waveguide grating comprising a plurality of channel waveguides, each said channel waveguide having a predetermined length difference in accordance with said predetermined wavelength difference, so that each said signal at different wavelength is provided with a phase difference from each other in accordance with said predetermined length difference; an output slab waveguide for focusing each said signal at different wavelength emerging from said channel waveguides into a plurality of predetermined positions in accordance with said predetermined wavelength difference, respectively; and a plurality of output channel waveguides, an input end of each said output channel waveguide being arranged at each said predetermined position so that each separated signal is coupled to each said output channel waveguide and emerges from an output end thereof; wherein a loss of each said output channel waveguide is selected in accordance with loss differences between said separated signals coupled into said output channel waveguides.