Effect of waveguide structure on beam quality and power of 905 nm cascade semiconductor lasers with tunnel junctions

In recent years, lidar applications had put forward higher requirements for detection distance and sensitivity. As an ideal light source, 905 nm semiconductor lasers also urgently needed to improve the peak power and beam quality. In this context, the effects of different gain region types and waveguide structures on beam quality and power efficiency of 905 nm tunnel-junction pulsed semiconductor lasers were investigated based on asymmetric large optical cavity structures. By optimizing the gain region type and waveguide structure, the bulk resistance and internal loss were reduced. The ability to limit carrier leakage was enhanced, and the peak power and electro-optical efficiency of the device working at high currents were improved. By increasing the threshold gain ratio of the multimode to the fundamental mode, the high-order mode lasing was suppressed, and the far-field divergence angle was reduced. On this basis, the developed quadruple-active regions semiconductor laser with 800 μm cavity length and 200 μm electrode achieved a peak power output of 177 W at a pulse current intensity of 41.6 A in pulse power test with a pulse width of 100 ns and a repetition rate of 1 kHz; fundamental mode emitting in the vertical direction, the full width at half maximμm far-field divergence angle was 24.3°.