JPS5524418A - Light integrated circuit - Google Patents

Abstract

PURPOSE:To integrate active layer and light waveguide path by selecting materials such that an active layer of III-V group compound semiconductor laser is small in prohibited band width and large in refractive index as compared with adjacent layers, and a light waveguide path is large in prohibited band width and also in refractive index. CONSTITUTION:A buffer layer 22 of Ga0.20In0.80P0.56As0.44 (prohibited band width being 0.98eV, refractive index 3.42) is formed on (100) face of InP 21 epitaxially, a light waveguide path 23 of Ga0.40In0.60P0.57As0.23Sb0.20 (prohibited band width being 0.99eV, refractive index 3.43) is grown, an active layer 25 of Ga0.22In0.78P0.51As0.49 (prohibited band width being 0.97eV, refractive index 3.43) is further grown by way of an intermediate layer 24 same in composition as the layer 22, and finally a layer 26 same in composition as the layer 22 is placed thereon. An IC for which light waveguide path and laser are integrated is obtainable through resonating heterojunction according to the well-known method and providing a resonator 27 of a dispersion feedback construction 27, pn junction and electrode. Light signals can thus be trasmitted effectively to a long distance even if a loss of the light waveguide path is minimized.