Method for producing an integrated optical circuit

A method for producing an integrated optical circuit comprising an active device and a passive waveguide circuit, the method comprising:

• applying an active waveguide structure on a source wafer substrate;
• exposing a portion of the source wafer substrate by selectively removing the active waveguide structure;
• applying a passive waveguide structure on the exposed portion of the source wafer substrate, wherein an aggregation of the active waveguide structure and the passive waveguide structure forms the active device, the active device having a bottom surface facing the source wafer substrate;
• removing the source wafer substrate from the active device;
• and
• attaching the active device to a target substrate comprising the passive waveguide circuit such that the bottom surface of the active device faces the target substrate,
• wherein applying the active waveguide structure on the source wafer substrate comprises growing a III-V thin-film on the source wafer substrate, and
• wherein applying the passive waveguide structure on the exposed portion of the source wafer substrate comprises re-growing the III-V thin-film on the exposed portion of the source wafer substrate.