Fiber optic system for high frequency burst operation of a silicon carbide photoconductive semiconductor switch

A fiber optic system was constructed to demonstrate high frequency operation of a silicon carbide (SiC) photoconductive semiconductor switch (PCSS). The goal was to transform a single high-energy laser pulse into a train of pulses by adding static delays into a multimode fiber bundle. The individual optical fibers comprising the fiber bundle incrementally add an additional amount of flight time to the light pulse. The end result is a train of pulses with a fixed delay between each pulse. A frequency-tripled Nd:YAG laser (10 ns FWHM) generating up to 300 mJ of light energy at 355 nm is coupled from free space into the optical fibers comprising the fiber light guide. Experimental results examining the collection and transmission efficiency, and the temporal output are presented.