Optical waveguide filters for the visible spectrum

A study has been made of wavelength selective devices which use a grating structure superimposed on a thin film optical waveguide. Good agreement was found between the theoretical and experimental wavelength response of filters in three forms of optical waveguide: with the grating ion-beem etched into a single homogeneous guiding layer, with the grating in a photoresist film on a homogeneous layer and with the grating in a photoresist film on a silver ion-exchanged waveguide. Details of the method of fabrication of the gratings and waveguides are given. Filters made with gratings ion-beanm etched into waveguide had bandwidths of 0.2 to 0.5 nm at 600 nm while the filters with superimposed gratings in photoresist had somewhat wider bandwidths.