Photonic device comprising a laser optically connected to a silicon wave guide and method of fabricating such a photonic device

Method of fabrication of a photonic device comprising at least one silicon waveguide and a laser comprising a gain medium capable of emitting light, the method comprising the following steps:

• supply a substrate associated with a first silicon layer on a first dielectric layer,
• pattern the first silicon layer to form, in the first silicon layer, at least part of the thickness of a waveguide, and first to fifth waveguide sections distinct from the waveguide, 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,
• formation of a first and a second excess thickness of silicon separated from each other by a space, the first and the second excess thicknesses and the space facing the second, fourth and third waveguide sections respectively or zones of the first silicon layer that will formed its,
• burial of at least the first and second excess thicknesses of silicon by at least one dielectric material and planarisation of said dielectric material to form an intermediate layer, an assembly composed of the substrate/first dielectric layer/first silicon layer/intermediate layer thus being formed,
• supply a support,
• assemble the substrate/first dielectric layer/first silicon layer/intermediate layer assembly on the support, the assembly being made by bonding the intermediate layer on the support,
• eliminate the substrate,
• formation of a gain structure comprising at least the gain medium, the gain structure being formed in contact with the first dielectric layer and having a central portion of the gain structure 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, the photonic device thus being formed,
• and wherein a feedback structure is also formed to form an oscillating cavity comprising at least partly the gain medium and thus form a laser optically connected to the waveguide by at least one of the first and the fifth waveguide sections during at least one of the steps among the step to pattern the first silicon layer and the step to form the first and the second excess thicknesses of silicon.