Optical demultiplexer for a wavelength division multiplexing system.

A wavelength division multiplexing (WDM) technique, which transmits signals with different wavelengths by means of a single optical fiber, can increase the capacity of optical fiber transmission systems. This paper describes the experimental results of a demultiplexer using a diffraction grating for a WDM system. The insertion loss of the demultiplexer could be decreased by using a large core output fiber, an Au-coated diffraction grating, and small aberration lenses. There were five channels in the 0.8-microm wavelength region. Wavelength spacing was 200 A. Insertion loss for each channel was about 2 dB, and cross talk was <-30 dB.