Phase modulator and method for producing same

A method for producing at least one thermo-optic phase modulator comprising a stack in a first direction, said stack comprising a waveguide configured to guide a light beam of wavelength λ in a second direction, an encapsulation layer surmounting the waveguide, a so-called heating element configured to heat the waveguide and surmounting the encapsulation layer, said modulator further comprising first and second trenches extending on either side of the stack, the method comprising:

• A formation of a base stack comprising, in the first direction, a waveguide pattern, an initial encapsulation layer surmounting the waveguide pattern, and the heating element surmounting the initial encapsulation layer,
• An etching of the base stack in the first direction, configured to form the first and second trenches and the stack bordered by said first and second trenches, the waveguide being obtained from the waveguide pattern, and the encapsulation layer being obtained from the initial encapsulation layer,
• the method being wherein the heating element forms an etching mask during the formation by etching of the first and second trenches, such that the waveguide, the encapsulation layer and the heating element each have first and second flanks such as the first flanks of the waveguide, of the encapsulation layer and of the heating element form at least partially one flank of the first trench, and the second flanks of the waveguide, of the encapsulation layer and of the heating element form at least partially one flank of the second trench.