PURPOSE: To allow a lateral mode control structure by employing a superlattice structure formed of a group II-VI semiconductor as an active layer, thermally converting the superlattice structure into mixed crystal structure through irradiation with laser beam except stripe regions for forming waveguides, and forming the waveguide of a semiconductor having average composition.
CONSTITUTION: A ZnSSe/ZnCdSSe superlattice active layer 3 is formed by laminating ZnSSe layers 6 and ZnCdSSe layers 7 alternately in four layers. An SiO2 protective film 8 is then deposited thereon through thermal CVD, followed by deposition of a Cr film 9 in string and irradiation with Ar ion laser beam. Consequently, temperature rises in the ZnSSe/ZnCdSSe superlattice layer 3 which is thereby converted into mixed crystal thus producing a ZnCdSSe layer 10. In this regard, the Cr film 9 reflects the laser beam and produces no mixed crystal. This constitution allows a lateral mode control structure requiring no shaping of group II-Vi semiconductor.
UDA MASAHITO
YANO SHINICHIRO
