Low-loss optical demultiplexer for WDM systems in the 0.8-microm wavelength region

A low-loss small-sized demultiplexer using a diffraction grating in the Littrow mounting is realized for a wavelength division multiplexing (WDM) system for optical fiber systems. The system has five channels and a wavelength spacing of 200 A in the 0.8-microm region. Insertion loss was about 1.7 dB in each channel, and cross talk was <-30 dB. These characteristics make this demultiplexer the most suitable device available for optical fiber systems employing WDM configurations.