A photonic integrated circuit includes a first insulating region encapsulating at least one metallization level, a second insulating region at least partially encapsulating a gain medium of a laser source, and a stacked structure placed between the two insulating regions. The stacked structure includes a first polycrystalline or single-crystal silicon layer, a second polycrystalline or single-crystal silicon layer, an intermediate layer optically compatible with the wavelength of the laser source and selectively etchable relative to silicon and that separates the first layer from a first portion of the second layer, and the gain medium facing at least one portion of the first layer. The first layer, the intermediate layer, and the first portion of the second layer form an assembly containing a resonant cavity and a waveguide, which are optically coupled to the gain medium, and a second portion of the second layer containing at least one other photonic component.