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- ItemWavelength-stabilized ns-pulsed 2.2 kW diode laser bar with multiple active regions and tunnel junctions(Stevenage : IET, 2022) Ammouri, Nor; Christopher, Heike; Fricke, Jörg; Ginolas, Arnim; Liero, Armin; Maaßdorf, Andre; Wenzel, Hans; Knigge, AndreaThe improvement of the performance of a distributed Bragg reflector laser bar emitting near 905 nm through the use of multiple epitaxially stacked active regions and tunnel junctions is reported. The bar consisting of 48 emitters (each having an aperture of 50 µm) emits an optical power of 2.2 kW in 8 ns long pulses at an injection current of 1.1 kA. This corresponds to an almost threefold increase of the pulse power compared to a bar with lasers having only a single active region. Due to the integrated surface Bragg grating, the bar exhibits a narrow spectral bandwidth of about 0.3 nm and a thermal tuning of only 68 pm/K.
- ItemVersatile high power pulse-laser source for pico- and nanosecond optical pulses(London : Institute of Physics, 2020) Liero, Armin; Klehr, Andreas; Knigge, Andrea; Heinrich, WolfgangThis paper presents a pulse-laser source for the generation of ps and ns laser pulses with more than 50 W peak output power. The final stages of the drivers use GaN transistors and are capable of switching currents of 0.8 A with 200 ps minimum pulse width and 50 A with 3 ns minimum pulse width. The pulses can be externally triggered by ECL logic. Both single-pulse and pulse train modes are possible.
- ItemWavelength stabilized high pulse power 48 emitter laser bars for automotive light detection and ranging application(Bristol : IOP Publ., 2020) Klehr, Andreas; Liero, Armin; Christopher, Heike; Wenzel, Hans; Maaßdorf, Andre; Della Casa, Pietro; Fricke, Jörg; Ginolas, Arnim; Knigge, AndreaDiode lasers generating optical pulses with high peak power and lengths in the nanosecond range are key components for light detection and ranging systems, e.g. for autonomous driving and object detection. We present here an internally wavelength stabilized distributed Bragg reflector broad area laser bar with 48 emitters. The vertical structure based on AlGaAs (confinement and cladding layers) and InGaAs (active quantum well) is specifically optimized for wavelength-stabilized pulsed operation, applying a surface Bragg grating with high reflectivity. The bar is electrically driven by a new in-house developed high-speed driver based on GaN transistors providing current pulses with amplitudes of up to 1000 A and a repetition frequency of 10 kHz. The generated 4 ns to 10 ns long optical pulses are nearly rectangular shaped and reach a pulse peak power in excess of 600 Watts at 25 °C. The optical spectrum with a centre wavelength of about 900 nm has a width of 0.15 nm (FWHM) with a side mode suppression ratio > 30 dB. © 2020 IOP Publishing Ltd.