PHOTON INTEGRATED CIRCUIT AND ITS FABRICATION METHOD

PROBLEM TO BE SOLVED: To make a surface of a photon integrated circuit flat by growing a waveguide stack including a waveguide layer and an active layer on a substrate, forming a waveguide by etching partially, growing blocking layers on an active region and a passive waveguide, forming a trench on the active region and covering the trench by filling a clad layer in the trench. SOLUTION: An epitaxial growth of a primary waveguide stack is made on a substrate 21. A first layer 22 constitutes a passive waveguide layer on which a second passive guide layer 23 is provided. A third layer 23 is an active multi-quantum well layer which forms, a laser active layer and a fourth layer 25 constitutes a protective layer. An active region and a passive region of a photon integrated circuit(PIC) are formed by chemical etching with a mask and blocking regions are formed by a second epitaxial growth. The blocking layers on the active region are selectively removed so as to form a recess and the surface of the PIC is held flat except for this recess. A clad layer 31 is prepared to fill this recess so as to make the surface of the PIC flat.