Study on the polarization control in tapered semiconductor lasers

Tapered semiconductor lasers have gained significant attention for their capability to achieve both high power and high beam quality. These lasers consist of an index-guided ridge waveguide and a gain-guided tapered amplifier. By implementing deep etching in the ridge section and introducing on-chip compressive stress in the tapered amplifier, the degree of polarization and beam quality of the laser output are improved. Combining the methods above, the polarization mismatch between the ridge and tapered sections is addressed and amplification efficiency is enhanced. The fabricated InGaAs/AlGaAs compressive strain single quantum well laser, emitting at a wavelength near 1μm, achieves continuous wave output of 11.57 W at tapered current of 14 A, with a degree of polarization exceeding 90%.