Optical branching waveguide.

摘要

An optical branching waveguide having low radiative loss and low back-reflectivity is described. By employing between the branches (340,360) a region (380) having a gradual decrease in effective refractive index along the direction of optical propagation, the deleterious effect of wedge tip truncation can be reduced. According to the teachings of the invention, this may be accomplished by gradually decreasing the thickness of the optical material along the axis of optical propagation and planarizing the region with an optical material having an lower refractive index than the underlying optical material. <IMAGE>