Implementation of energy barrier layers for 1550 nm high-power laser diodes

The influence of a thin AlInAs energy barrier on the efficiency of 1550 nm high-power semiconductor lasers efficiency has been experimentally studied. It was shown that the position and number of barriers in an asymmetric laser heterostructure based on a 1.8–1.9 μm thick waveguide has a significant effect on the output optical power. It is shown that in a barrierless structure, the main reason for radiative efficiency decrease is internal quantum yield drop due to the absence of an energy barrier for the type-II heterojunction at the waveguide-p-cladding interface and electron leakage to the p-emitter layer. It is demonstrated that the implementation of single AlInAs energy barrier layer on waveguide-p-cladding heterojunction allows significantly increase laser diode maximum output power. 2 W maximum CW optical power has been achieved from 40 μm aperture laser diode at heatsink temperature 25 °C. •AlInAs energy barrier layers are crucial to stop the carrier leakage.•Best barrier layer location is between AlGaInAs p-waveguide and InP p-cladding layers.