High peak optical power of 1ns pulse duration from laser diodes – low voltage thyristor vertical stack

It is shown that the use of low-voltage GaAs/AlGaAs thyristors as high-speed and high-current switches in vertical stacks with semiconductor lasers ensures the efficient generation of high-power ns-duration laser pulses. The lasing and current dynamics in vertical stacks based on laser diode mini bar emitting at 1060 nm and a single as well as a double thyristor switch is studied. The possibility is demonstrated that a laser diode mini bar (with 3 laser emitters) together with a single thyristor switch can generate laser pulses with a peak power of 6 W with a duration of 950 ps and a peak current of 12 A for an operating voltage of 28 V. The use of a double thyristor switch leads to a broadening of the current pulse due to different delays in turn-on of the thyristor switches, while the peak power and duration of laser pulses increase to 8 W and 1.4 ns, respectively. It is found that the stage of low-speed turn-on of the thyristor limits the efficient generation of current and laser pulses of ns duration at low operating voltages (less than 21V). An efficient generation of current and laser pulses by low-voltage thyristors at control currents of 2-320 mA is ensured by efficient impact ionization in the region of the reverse biased p-n junction at high values of operating voltages (more than 21V).