High-efficiency and high-power AlGaAs/ GaAs laser

Light output of 60 mW from the front facet of an AlGaAs/ GaAs SBH laser is obtained in CW operation at room temperature in a junction-up configuration. External quantum efficiency of the facet attains to 52 percent at several milliwatts region in CW operation. The high efficiency enables the laser to oscillate in high power CW operation for the junction-up assembling, and is consistent with a value calculated from the cavity length, refleetivities, and internal loss estimated in this work. The reflectivity of the rear facet has been increased to 0.61 by three-layer coating of SiO
2
/a-Si/SiO
2
. The front facet has been passivated by Si
3
N
4
film deposited by plasma CVD technique. The thickness of the film is controlled so as to decrease the reflectivity of the facet to 0.25. The characteristic temperature of the threshold is estimated to be 120 K. Mode behaviors and high temperature operations are also described.