Phase change material switch

A switch based on a phase-change material comprising:

• a region of said phase-change material coupling first and second conduction electrodes of the switch;
• a waveguide located vertically in line with the region of said phase-change material and comprising a central region of a first material having a first refractive index surrounded by a peripheral region of a second material having a second refractive index lower than the first refractive index, the waveguide being adapted to transmit an optical control signal of the switch;
• and
• a region of a third material having a third refractive index lower than the second refractive index and located in the peripheral region of the waveguide vertically in line with a first face of the central region of the waveguide opposite the region of said phase-change material.