| 摘要 |
PURPOSE:To realize large-scale integration by a method wherein two or more waveguide layers are formed in an upward direction and a downward direction and they are united to one output waveguide near a beam radiation end. CONSTITUTION:A stepped part is formed on the surface of an n-InP substrate 1; a diffraction grating 3 is formed partially at the bottom of the stepped part 2; after that, an n-In0.72Ga0.28As0.61P0.39 waveguide layer 4, an undoped In0.59Ga0.41 As0.90P0.10 active layer 5 and a p-InP clad layer 6 are laminated. Then, the clad layer 6 and the active layer 5 other than the upper part of the diffraction grating 3 are etched selectively; an insulating film 7 is formed in a part of a plateau (a plateau part) of the stepped part; a p-InP clad layer 8 and an Fe-doped high-resistance InP layer 9 are formed selectively in a part other than the plateau part. Accordingly, the waveguide layer 4 becomes one common output waveguide layer 12 at the plateau part of the stepped substrate. By this setup, it is possible to obtain an optically integrated device which has been integrated on a large scale and whose optical coupling to other optical circuits is good. |
