| Popis: |
Diode lasers providing nanosecond optical pulses with high peak optical powers are key components in systems for freespace communication, metrology, material processing, spectroscopy, and light detection and ranging (LIDAR) as employed for, e.g., autonomous driving. Here, we report on laser sources for line-scanning automotive LIDAR systems. The laser sources are implemented as distributed Bragg reflector diode lasers bars featuring 48 broad area emitters each with a 50 μm wide mesa structure. The epitaxial layer structure comprising an AlGaAs-based waveguide and InGaAs single quantum well is optimized for pulsed operation at a wavelength of around 905 nm. For a temperature-dependent wavelength shift as low as approx. 60 pm/K, each emitter features a surface-DBR grating. The DBR laser bars are mounted p-side down on CuW submounts and sandwiched between a thin electronic driver board and a mount to minimize inductances. The in-house developed electronic driver generates 2 ns to 10 ns long current pulses with peak current up to 1000 A. With 8 ns long optical pulses and a peak current of about 900 A, a peak optical power of about 640 W is achieved at 25°C. Integration of the diode laser with micro-lenses and a beam twister provides a homogeneous line by individual projection of each of the 48 emitters with divergence angles of 24 deg x 0.1 deg (full width at 1/e2 intensity) in the vertical and horizontal direction, respectively. |
