A Compact High Current Driver for Semiconductor Diode Lasers, Suitable for Laser Radar (LADR) Applications

A fast-pulsed (3-15ns FWHM) high-current (>500A) driver for high power diode lasers or laser arrays is proposed. Present high-current diode drivers typically use MOSFET switches to modulate the current. It is difficult to achieve very fast pulses with such devices because the inherent capacitance of the gate electrode cannot be charged and discharged quickly. Lower current, but faster diode drivers exist that use single avalanche transistors as the output device. This proposal differs from previous work in that a parallel array of avalanche transistors would be employed as a pulse sharpening output witch for the pulser. To achieve a current pulse >500A, several parallel output transistors modules will drive the diode laser load. The parallel architecture naturally leads to the low inductance configuration required for a fast, high-current pulser. The Phase I effort will demonstrate a prototype high-current pulser. In Phase II, the diode driver will be integrated into an operating LADAR system. Diode laser drivers have not kept up with the improvements in the diode lasers themselves. In order to fully utilize the potential of diode lasers for laser radar, a compact high-power electrical driver is required. An improved driver would have a direct impact on LADAR systems used as seekers on air-air and air-surface munitions. Potential applications for high-power laser radar in the commercial sector include low-cost collision avoidance systems, survey and ranging instruments, and laser velocimeters.