Megahertz high voltage pulse generator suitable for capacitive load

Yu Xu,Wei Chen,Sheng-Kai Liao,Yu-Huai Li,Fu-Tian Liang,Qi Shen,Hao Liang,Cheng-Zhi Peng

doi:10.1063/1.5006827

Abstract

A high voltage pulse generator is presented to drive Pockels cell. The Pockels cell behaves like a capacitor which slows the rise/fall time of the pulse and restrains the repetition rate of the generator. To drive the Pockels cell applied in quantum communication system, it requires about 1 MHz repetition rate with the rise/fall time of the pulse less than 50 ns, adjustable amplitude up to 800 V and an adjustable duration. With the assistance of self-designed transformers, the circuits is simplified that a pair of high current radio frequency (RF) MOSFET drivers are employed to switch the power MOSFETs at a high speed, and the power MOSFETs shape the final output pulse with the requirements. From the tests, the generator can produce 800 V square pulses continously at 1 MHz rate with 46 ns in risetime and 31 ns in falltime when driving a 51 pF capacitive load. And the generator is now used to drive Pockels cell for encoding the polarization of photons.

Highlights

Linear electro-optic effect, known as the Pockels effect, is widely used for modulating amplitude, polarization or phase of photons
The push-pull configuration based on power MOSFET have both nanosecond rise and fall times,[12,13] this generator is adapted for capacitive load and has a powerful driving capability for the Pockels cell, but the repetiton rate is still low or not mentioned in these works
Because the primary isolation transformer T1 can be equivalently regarded as an inductor L1, the H-trigger signals, which turns on the power MOSFET Q1, will pass through an RLC circuit

Summary

INTRODUCTION

Linear electro-optic effect, known as the Pockels effect, is widely used for modulating amplitude, polarization or phase of photons. Achieving the high voltage together with the demands of a fast rise/fall time and high repetition rate is the main goal and the difficulty when building drivers for Pockels cells for quantum information experiments. The Pockels cell behaves like a capacitor, so the high voltage pulse generator designed for a Pockels cell realizes fast charging and discharging of a capacitive load, which slows the rise/fall time of the pulse, releases extra heat and turns out to be one of the bottlenecks when raising the repetition rate. The push-pull configuration based on power MOSFET have both nanosecond rise and fall times,[12,13] this generator is adapted for capacitive load and has a powerful driving capability for the Pockels cell, but the repetiton rate is still low or not mentioned in these works. The generator is designed for capacitive load, and it has wide application prospects where high voltage pulse generators is demanded

THE CIRCUITS

Gate driver circuit

Pulse generator circuit

CONCLUSION