High-Energy Picosecond Pulse Generation by Gain Switching in Asymmetric Waveguide Structure Multiple Quantum Well Lasers

A multiple quantum well laser diode utilizing an asymmetric waveguide structure with a large equivalent spot size of ~3 μm is shown to give high energy (~1 nJ) and short (~100 ps) isolated optical pulses when injected with <;10 A and ~1-ns current pulses realized with a MOS driver. The active dimensions of the laser diode are 30 μm (stripe width) and 3 mm (cavity length), and it works in a single transversal mode at a wavelength of ~0.8 μm. Detailed investigation of the laser behavior at elevated temperatures is conducted; it is shown that at high enough injection currents, lasers of the investigated type show low temperature sensitivity. Laser diodes of this type may find use in accurate and miniaturized laser radars utilizing single photon detection in the receiver.