Semiconductor laser source designed to emit at at least one wavelength λ Li, this laser source comprising: - a substrate made of silicon extending mainly in a plane called "plane of the substrate", - a structured layer (6; 82; 102) formed on an upper face of the silicon substrate and having an upper face on the side opposite to the silicon substrate, this structured layer comprising: • a passive optical component (20; 84; 103) chosen from within the group composed of an optical reflector and of a waveguide, this passive optical component being encapsulated in silica or formed on a layer of silica, and • at least one plug extending from a lower face, in direct contact with the silicon substrate, up to an upper face being flush with the upper face of the structured layer, this plug being entirely formed from a material whose thermal conductivity at 20° C is greater than the thermal conductivity of silica at 20° C so as to form a thermal bridge through the structured layer, - an optical amplifier (8; 94) made of a III-V material designed to amplify the optical signal of wavelength λ Li which is passing through it when it is powered, this optical amplifier being directly bonded, by direct bonding, onto the upper face of the structured layer above - in a direction perpendicular to the plane of the substrate - onto the passive optical component in such a manner that the optical signal amplified by the optical amplifier is reflected or guided by this passive optical component, this optical amplifier also being directly bonded, by direct bonding, at least in part, onto the upper face of the plug in order to dissipate the heat that it generates towards the silicon substrate, characterized in that the plug is made of silicon nitride. - a substrate made of silicon extending mainly in a plane called "plane of the substrate", - a structured layer (6; 82; 102) formed on an upper face of the silicon substrate and having an upper face on the side opposite to the silicon substrate, this structured layer comprising: • a passive optical component (20; 84; 103) chosen from within the group composed of an optical reflector and of a waveguide, this passive optical component being encapsulated in silica or formed on a layer of silica, and • at least one plug extending from a lower face, in direct contact with the silicon substrate, up to an upper face being flush with the upper face of the structured layer, this plug being entirely formed from a material whose thermal conductivity at 20° C is greater than the thermal conductivity of silica at 20° C so as to form a thermal bridge through the structured layer, • a passive optical component (20; 84; 103) chosen from within the group composed of an optical reflector and of a waveguide, this passive optical component being encapsulated in silica or formed on a layer of silica, and • at least one plug extending from a lower face, in direct contact with the silicon substrate, up to an upper face being flush with the upper face of the structured layer, this plug being entirely formed from a material whose thermal conductivity at 20° C is greater than the thermal conductivity of silica at 20° C so as to form a thermal bridge through the structured layer, - an optical amplifier (8; 94) made of a III-V material designed to amplify the optical signal of wavelength λ Li which is passing through it when it is powered, this optical amplifier being directly bonded, by direct bonding, onto the upper face of the structured layer above - in a direction perpendicular to the plane of the substrate - onto the passive optical component in such a manner that the optical signal amplified by the optical amplifier is reflected or guided by this passive optical component, this optical amplifier also being directly bonded, by direct bonding, at least in part, onto the upper face of the plug in order to dissipate the heat that it generates towards the silicon substrate,