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For automotive light detection and ranging (LiDAR) systems diode lasers emitting short optical pulses with a good beam quality and a low wavelength shift over a wide operating temperature range is needed. In this paper, theoretical and experimental results of broad area laser diodes specially designed for this application are presented. Optical pulse powers of tens of watts and pulse lengths in the 10 ns-range for wavelengths near 905 nm and environmental temperatures between 15 and 85 C are achieved. Due to the integrated Bragg grating the wavelength shift with temperature is as low as 65 pm K À1 . The contact mesa with a width of 50 μm leads to a lateral M 2 value of about 9. Streak camera measurements of the temporal evolution of the lateral near field intensity reveal that the highest intensity is emitted near the mesa edges. Simulation results of power current characteristics indicate that the power saturation experimentally observed can be attributed to nonlinear effects such as two-photonabsorption and gain compression.

Almost chirp-free pulses with a duration of 190 fs were achieved from a mode-locked semiconductor disk laser (SDL) emitting at approximately 1045 nm. Pulse shaping was different from the soliton-like mode-locking process known from lasers using dielectric gain media; passive amplitude modulation provided by a fast saturable absorber was essential. The spectrum of the absorber had to be matched to the gain spectrum within a few nm. A tapered diode amplifier was demonstrated to be a device for both picking and amplifying SDL pulses. The pulse repetition rate of the SDL output was reduced from 3 GHz to 47 MHz.

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A GaN-HEMT-based circuit is presented capable of switching 20 A of current with less than about 0.5 ns rise and fall time. This demonstrates the potential of GaN transistors for high current switching applications, even if breakdown voltage re quirements are low. The current driver is used to realize an opti cal pulse picker generating 10 ps optical pulses of more than 30 W with a variable repetition rate between 1 kHz and 100 MHz.