Abstract
In this Letter, we report on a new structure of 1.3-μm AlGaInAs strain-compensated multiple-quantum-well laser diodes (SC-MQW LDs) by introducing an AlGaInAs graded-composition layer into the outside of the conventional graded-index separate-confinement heterostructure (GRINSCH) structure to enhance the carrier injection and thus reduce the threshold current. This new-structure 3-μm ridge-stripe LDs without facet coating exhibit an extremely low threshold current of 9 mA, a light output power of 20 mW at 100 mA, a characteristic temperature of 80 K in the operating temperature of 20-70°C, an operating temperature exceeding 90°C with a threshold current lower than 30 mA, and a red-shift rate of 0.4nm/°C.