The invention relates to a process for manufacturing an integrated optical device comprising the deposition on a support substrate of a multilayer being formed by first and second cladding layers in order to hold in a multilayer first region a waveguide core layer. The core is provided with an electromagnetic radiation (L) inlet/outlet port. Furthermore, the process provides for the formation of a regulation layer having a first etching speed associated therewith, which is distinguished from the etching speeds of the cladding layers. Subsequently to an etching of a multilayer second region, a cavity is obtained having a first wall which is inclined relative to the substrate at least partially extending in said first region and which is near said inlet/outlet port. Such etching removes portions of the regulation layer and the cladding layers at different speeds in order to result in the formation of the inclined wall.