Method of fabricating optical waveguides for the mid- infrared spectrum

Abstract From the Canadian patent

A method of fabricating optical waveguides for the mid-infrared spectrum, consisting of masking the surfaces of a suitable substrate to expose only those regions where the optical guide is to be fabricated, and immersing the masked substrate into a fused salt of a doping compound consisting of a cation bonded to a fluoride at high, temperature, to permit doping of the substrate. Ionic exchange in remaining regions of the substrate is prevented. An electric field may be applied to accelerate the doping process.