Photonic device comprising: - a support , - an intermediate layer in contact with the support and comprising at least one dielectric material and a first and second excess thickness of silicon , the first and second excess thicknesses of silicon being separated from each other by a space , - a first silicon layer in contact with the intermediate layer opposite the support , the first silicon layer comprising at least part of the thickness of a waveguide , and first to fifth waveguide sections distinct from the waveguide 200, the first to the fifth waveguide sections succeeding each other and being optically connected to the waveguide by at least either the first or the fifth waveguide section , the second, the fourth and the third waveguide sections facing the first and second excess thicknesses and the space , respectively, - a first dielectric layer covering the first silicon layer opposite the intermediate layer , - a gain structure comprising at least one gain medium capable of emitting light, the gain structure having a central portion facing the space and a first and a second end facing the first and the second excess thicknesses , thus the central portion of the gain structure with the space and the third waveguide section forms a hybrid laser waveguide, the second and the fourth waveguide sections , the first and the second excess thicknesses of silicon and the first and the second ends of the gain structure forming a first and a second optical transition zone of an optical mode between the hybrid laser waveguide and the first and fifth waveguide sections respectively, - a feedback structure to form an oscillating cavity comprising at least part of the gain medium so as to form a laser optically connected to the waveguide by at least either the first or the fifth waveguide section . - a support , - an intermediate layer in contact with the support and comprising at least one dielectric material and a first and second excess thickness of silicon , the first and second excess thicknesses of silicon being separated from each other by a space , - a first silicon layer in contact with the intermediate layer opposite the support , the first silicon layer comprising at least part of the thickness of a waveguide , and first to fifth waveguide sections distinct from the waveguide 200, the first to the fifth waveguide sections succeeding each other and being optically connected to the waveguide by at least either the first or the fifth waveguide section , the second, the fourth and the third waveguide sections facing the first and second excess thicknesses and the space , respectively, - a first dielectric layer covering the first silicon layer opposite the intermediate layer , - a gain structure comprising at least one gain medium capable of emitting light, the gain structure having a central portion facing the space and a first and a second end facing the first and the second excess thicknesses , thus the central portion of the gain structure with the space and the third waveguide section forms a hybrid laser waveguide, the second and the fourth waveguide sections , the first and the second excess thicknesses of silicon and the first and the second ends of the gain structure forming a first and a second optical transition zone of an optical mode between the hybrid laser waveguide and the first and fifth waveguide sections respectively, - a feedback structure to form an oscillating cavity comprising at least part of the gain medium so as to form a laser optically connected to the waveguide by at least either the first or the fifth waveguide section . <EOS>