Design of a High Speed Electro-optic Q-switch Circuit for Aerospace Applications

Abstract

In order to meet the requirements of high amplitude and high speed of electro-optic Q-switch voltage, a high speed electro-optic Q-switch circuit for aerospace applications is designed. According to the principle of Marx generator, the circuit uses a high speed driving chip to drive the switching transistor to conduct. The charge of the primary energy storage capacitor of the pulse transformer is quickly released, and the secondary induced voltage drives the switches of the Marx generator to open quickly and synchronously. By utilizing the fast and synchronous opening of MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), cascaded discharge is carried out on the energy storage capacitors of the 8th order Marx generator circuit, thereby outputting high voltage pulse signal. The experimental results show that the Marx generator has maximum boost output range of 4000V and high voltage pulse rise time of less than 30ns. Compared to traditional pulse transformer control methods, the Q-switch voltage rise time is reduced by nearly 40ns. The internal components of circuit meet the requirements of multiple indicators such as anti-irradiation space environment, and have the characteristic of short output high voltage rise time, which can provide high speed and high voltage driving pulses for the electro-optic Q-switch crystal inside the laser cavity.