Fiber-Optic Controlled PCSS Triggers For High Voltage Pulsed Power Switches

Abstract

Pulsed power systems are continually being designed to increase performance and flexibility in order to meet new needs. Drivers for fusion, equation of state research and radiography are just a few of the scientific areas driving accelerated pulsed power development. Improved system timing and jitter requirements, along with pulse shaping capabilities through independent timing of individual switches, are placing higher demands upon high voltage (HV) switch performance, triggering system performance and cost. Conventional trigger systems require high voltage trigger cables or line-of-sight optics that complicate design, demand space, require extensive maintenance, and significantly impact system cost. With electrical triggers, large diameter, high voltage transmission line cables must be fed through high field regions. With optical triggers, line-of-sight optics must focus high energy laser beams to the interior of the switches with clean, rigidly-mounted, shock-withstanding optics. This paper reports on progress in the development of fiber optically triggered photoconductive semiconductor switches (PCSS) for triggering high voltage pulsed power switches with improved precision. This technology can eliminate the need for large-diameter trigger cables and line-of-sight optics. It also has the potential of significantly reducing the cost of trigger generation systems. It has the potential to improve the performance of prime power switches, diverters, and diagnostics because of the low-jitter sub-nanosecond rise times. Test results will be presented that demonstrate sub-nanosecond jitter from a PCSS, less than 1.