High-performance 670-nm AlGaInP/GaInP visible strained quantum well lasers

We have grown high-performance AlGaInP/GaInP visible (670 nm) strained quantum well lasers by low-pressure metalorganic chemical vapor deposition, With AIInP cladding layer, a high-power AlGaInP/GaInP visible laser diode is achieved, Its threshold current is about 30 mA, The output power of this laser diode can maintain, at least, at 32 mW under continuous-wave (CW) operation at room temperature, High slope efficiency (0.8 mW/mA) and differential quantum efficiency (0.87) can be achieved. To improve beam quality, AlGaInP/GaInP visible lasers with and without depressed index cladding layer are theoretically and experimentally studied, From experimental results, the transverse beam divergence can be reduced from 41.4 degrees to 26.2 degrees while maintaining a low threshold current (from 36 mA to 46 mA), By using the transfer matrix method, our theoretical calculations are in good agreement with the experimental results.