Microsecond Pulse-Mode Operation Of A Micro-Integrated High-Power External-Cavity Tapered Diode Laser At 808 Nm

We investigate microsecond pulse-mode operation of a micro-integrated high-power diode laser based on volume Bragg grating external-cavity feedback around 808 nm. The laser system contains a tapered amplifier consisting of a ridge-waveguide section and a tapered section with separated electrical contacts. Thus, the diode laser system can be pulsed by modulating the injected current either to the ridge waveguide section (I-RW) or to the tapered amplifier section (I-TA). With a trigger signal of a 50 mu s pulse width and a 10 kHz repetition rate, comparing the modulation depth, peak output power, beam propagation factor, and spectral bandwidth, we conclude that the pulse-mode operation achieved by modulating the ITA gives better results than by modulating the IRW due to the decreased thermal effect. At a constant I-RW of 0.2 A and a modulated I-TA of 6.0 A, 4.3Wof peak output power is obtained with an emission spectral bandwidth with an upper bound of 0.2 nm, and a beam propagation factor in the slowaxis, M-slow(2), of 2.6 (1/e(2)). The modulation depth is almost 100%. The results show that the tapered diode laser system may be a good candidate for microsecond pulse-mode solid-state lasers. (C) 2020 Optical Society of America