Single-mode AlGaAs/InGaAs/GaAs lasers with a ultra narrow waveguide

The design of the AlGaAs/InGaAs/GaAs laser heterostructure with an ultra-narrow waveguide was developed and studies on the generation of high-power laser pulses with high beam quality were carried out. The heterostructure design included a 100-nm-thick waveguide and an InGaAs quantum well for a lasing at 1060 nm. For the studies the mesa-stripe geometry single-mode lasers with a 5.1-μm-width contact were fabricated. The mesa-stripe geometry parameters were optimized using a 2D-simulation of waveguide properties, taking into account the spatial distribution of temperature and gain. As a result, the divergence was of 18.5 and 5 degrees in the growth direction and parallel to the heterostructure layers, respectively. Studies of the light-current characteristics in the range of pulse durations of 5–1000 ns showed that the peak power of 1.75 W was limited by the catastrophic optical damage. The dynamics is associated with modes of high-quality factor that approach their threshold conditions at high pumping level. A spectral line of these modes is redshifted relative to a fundamental one.