Graded doping low internal loss 1060-nm InGaAs/AlGaAs quantum well semiconductor lasers*

Internal loss is a key internal parameter for high power 1060-nm InGaAs/AlGaAs semiconductor laser. In this paper, we discuss the origin of internal loss of 1060-nm InGaAs/GaAs quantum well (QW) AlGaAs separate confinement heterostructure semiconductor laser, and the method to reduce internal loss. By light doping the n-cladding layer, and stepwise doping the p-cladding layer combined with the expanded waveguide layer, a broad area laser with internal loss of 1/cm is designed and fabricated. Ridge waveguide laser with an output power of 350 mW is obtained. The threshold current and slope efficiency near the threshold current are 20 mA and 0.8 W/A, respectively.