High-Power 1.5- $\mu$ m Broad Area Laser Diodes Wavelength Stabilized by Surface Gratings

Wavelength stabilization against temperature variation of high-power broad area 1.5- $\mu \text{m}$ InGaAsP/InP laser diodes is demonstrated by employing surface gratings. The development targets application in eye-safe automotive LIDAR systems, which would benefit from deploying narrowband receiver filters to block ambient solar radiation for improved signal-to-noise ratio. The surface grating is monolithically integrated on the laser chip using nanoimprint lithography. The peak power of the lasers exceeded 6 W in pulsed mode, for an FWHM spectral width of 0.3 nm and a peak wavelength drift of only 0.1 nm/°C. The wavelength shift with temperature is reduced by five times compared to broad area high-power Fabry–Perot laser diodes typically employed in LIDAR systems.