Improved high-temperature characteristics in a thickness-tapered 1.3-μm beam-expander integrated ridge-waveguide laser

High-temperature performance of a beam-expander (BEX) integrated laser was dramatically improved by reducing the current leakage in both longitudinal and lateral directions. Proton implantation into the BEX region and a reverse-mesa structure were combined to improve the high-temperature characteristics. A threshold current of 23.1 mA at 85/spl deg/C and a very high-characteristic temperature T/sub 0/ (25/spl deg/C-85/spl deg/C) of 74 K were achieved. Stable operation for over 3000 h under a 10-mW output power at 70/spl deg/C were confirmed.