Fabrication of single-crystal semiconductor optical waveguides by solid-state diffusion

Optical surface waveguides have been fabricated by diffusing selenium into single-crystal CdS substrates to produce graded-composition CdS Se crystals. Planar guides which confine a beam in one dimension and guides produced by masked diffusion capable of two-dimensional beam confinement have been obtained. Evidence of guiding of light from a HeNe laser is provided by photographs and by measurements of spatial intensity profiles. Losses are estimated to be 10-15 dB/cm for one-dimensional guides and 30-40 dB/cm for two-dimensional guides.