Abstract

Lasers generating nanosecond optical pulses are key components for light detection and ranging (LiDAR) systems employed in autonomous vehicles or used to measure atmospheric parameters. Although semiconductor lasers are ideally suited to generate nanosecond pulses by simply switching the injection current on and off, the available pulse powers are either too low or the required current amplitudes are too high for many applications. Additionally, their optical spectra are too broad resulting in a poor signal-to-noise ratio. To reduce the currents, several laser diodes, separated by tunnel junctions, can be epitaxially stacked in series. A reduction of the width of the spectra and their shift with temperature can be achieved by monolithic integration of a Bragg grating.

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