| 摘要 |
PURPOSE:To obtain a good active layer by providing a substrate and a lattice matching superlattice layer in the intermediate between a diffraction grating and the active layer, thereby alleviating or reducing a crystal internal stress, crystal defect indispensably induced at crystal growth on the irregular surface of the grating. CONSTITUTION:A diffraction grating 100 is formed on an N-type InP clad layer (the first clad layer) 2 grown on an N-type InP substrate 1. The period of the grating 100 is 4,670Angstrom when the secondary period is used, and the grating is repeatedly formed in the depth of 1,500Angstrom in (100) direction. The grating 10 is formed by an oscillation light of 4,250Angstrom of He-Cd gas laser by a 2-luminous flux interference exposing method. A photowaveguide layer 3 is formed on the grating 100, and a superlattice layer 4 is formed thereon. The layer 4 is used for a quantum well layer and a barrier layer of InGaAsP, InP or InGaAs and InAlAs. |
