Method for manufacturing an integrated electro-optical device, and electro-optical device thus obtained

A method for manufacturing an electro-optical device (50) comprising the following steps:

• manufacturing an optical waveguide (5) in an electro-optical substrate (1) by annealed proton exchange comprising the steps of:
• a) exposing an area of a surface (2) of the substrate (1) to a source of protons so as to create in the substrate a layer (3) modified by proton exchange, said layer (3) extending over said area from the substrate surface (2) down to a shallow depth (P3) into the substrate, and b) thermally annealing the substrate in order to diffuse hydrogen ions from said layer (3) to a diffusion area (4) extending in the substrate around said layer (3) down to a deep depth (P4), in order to create an optical waveguide (5) in the diffusion area (4);
• depositing a pair of electrodes (6, 7), the optical waveguide (5) extending longitudinally between said pair of electrodes (6, 7);
• wherein the method includes, after the thermal annealing step, a step of machining from the surface (2) at least part of the substrate in an area of the optical waveguide (5) corresponding to a residue of said layer (3) to form a machined area (10, 11, 12) located at least partly between said pair of electrodes (6, 7), over a depth P of the order of the shallow depth (P3) of the layer (3) modified by proton exchange.