| 摘要 |
PURPOSE:To produce refractive index distribution in the surface of a substrate and facilitate variation of a propagation constant and a coupling constant along the longitudinal direction of a resonator and also facilitate sufficient control of a horizontal mode by employing a substrate containing a multilayer quantum well in which a mixed crystalline part is provided by introducing an impurity selectively. CONSTITUTION:A P-type AlwGa1-wAs cladding layer 1A and an MQW layer 2 are made to grow on a P-type GaAs substrate 1. The MQW layer 2 is composed of a P-type AlxGa1-xAs quantum well layer 2A and a P-type AlyGa1-yAs barrier layer 2B. Then an SiO2 film 3 is formed and patterned so as to leave the part to be used as a mask for diffusion of zinc (Zn). If Zn is diffused to the depth of about 5,000Angstrom , mixed crystallization is induced and the equivalent refractive index of that part becomes lower than the refractive index of the MQW layer 2. Then a corrugation 4 is formed and a P-type AlzGa1-zAs light guide layer 5 is formed. Successively, an I-type GaAs active layer 6 and an N-type AlzGa1-zAs cladding and cap layer 7 are formed. |
