An optical element has a substrate having or not having a channel for optical waveguide; and a material which has a refractive index higher than that of the substrate and is filled in the channel for optical waveguide or is disposed on the substrate; wherein the refractive index in a part of the material...http://www.google.fr/patents/US6826344?utm_source=gb-gplus-shareBrevet US6826344 - Optical element and method of fabrication thereof
