<title>A Four Channel 10-Nanometer Spacing Wavelength Demultiplexer</title>

Results on the development of an experimental four channel fiber optics Wavelength Division Multiplexing (WDM) system with 10 nanometer channel spacing will be presented. Data on WDM demultiplexers utilizing narrow band interference filters will be reviewed. Results on studies of wavelength stability of semiconductor lasers for WDM will also be presented.