Fiber-Induced Optical Reflective Cavity in a High-Voltage SiC Photoconductive Switch to Improve Photoelectric Responsivity

An optical reflective cavity in vertical extrinsic SiC photoconductive switches is developed to improve the light absorption or photoelectric responsivity with the fiber triggering. The optical reflective cavity consists of a total reflector, a center reflector, and a fiber to form a quasi-total internal light trap. The fiber with a core diameter of
$400 ~\mu \text{m}$
is inserted into a hole reflector. Both simulations and experiments reveal that the light absorption of the device has been improved significantly. Compared with traditional vertical devices without optical configuration, the device demonstrates a
$2.29\times $
improvement in photoelectric responsivity. Using the optical reflective cavity, the SiC photoconductive switch achieves a power capacity of 3.1 MW with a peak photocurrent of 141 A at a laser energy of 15 mJ.