<title>Critical comparison of DH, SCH, and GRIN-SCH-SQW 780-nm ridge-waveguide lasers</title>

Abstract

The operating characteristics of ridge-waveguide AlGaAs/GaAs lasers with conventional double heterostructure (DH), separate-confinement heterostructures (SCH), and graded-index separate-confinement heterostructure single quantum well (GRIN-SCH-SQW) active layer structures grown by metalorganic vapor phase epitaxy (MOVPE) technique are reported. For conventional DH and SCH structures, an undoped Al0.15Ga0.85As active layer was used for an emission wavelength of 780 nm. An undoped 30 angstroms GaAs quantum well was centered in the 3000 angstroms thick graded AlxGa1-xAs (x equals 0.2 - 0.55) GRIN-SCH region with linear Al profile. The lasers with GRIN-SCH-SQE active layer exhibited lowest threshold current density among these three structures. The conventional DH laser has been shown to have better beam qualities and lower astigmatism than the other two types of lasers. Reliable operation for more than 1500 hrs was achieved at 50 degree(s)C for conventional DH lasers. However, GRIN-SCH-SQW lasers with very thin active layer (<EQ 30 angstroms) showed much higher degradation rate.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.