Characteristics of grating-coupled GaAs-GaAlAs lasers

Two types of grating-coupled (GC) GaAs-GaAlAs lasers with an unpumped corrugated region have been fabricated in order to clarify the characteristics of GC lasers. From the theoretical consideration, the efficiency of the GC output power was found to depend on the unpumped region loss and the edge-emission loss. To reduce the unpumped region loss, we adopted the separate confinement heterostructure (SCH) in place of the double heterostructure (DH). By taking the SCH structure, about 10 times larger efficiency was obtained than that of DH structure. More improved efficiency would be obtained by the reduction of the edge-emission loss. For this purpose, we propose a new structure with roof-top reflectors, which is able to be made by chemical etching technique and to be made into the monolithically two-dimensional GC laser array.