Research On Beam Properties Of High Power Semiconductor Lasers

Currently, high-power semiconductor lasers diode are generally wide-stripe structure, but this kind of laser diode has the disadvantage of large output beam divergence angle, asymmetric light intensity distribution (usually a wide divergence angle 30°-60°in the direction perpendicular to junction plane, a narrow divergence angle 10°-20°in the direction parallel to the junction plane), transverse mode instability and other issues produced by the changes of the temperature field.Based on the theoretical analysis laser diode bar structure is analyzed on the impact of the horizontal and perpendicular far field divergence angle, longitudinal mode and transverse mode beam parameters. We designed two kinds of structure which improve the beam quality, one is Gaussian line distribution contact electrodes, and another is Large Optical Cavity.As for the beam quality deterioration due to the device self-heating effects, device process (ohmic contacts and heat sink treatment) has been optimized.A comprehensive discussion of a variety of semiconductor laser beam quality evaluation Indicators is presented in order to improve the beam quality, and doing analyses and comparing about beam properties of the device before and after optimization.