High-Voltage Driver Circuits for Electro-Optical RF Modulators

Pockels cells are used in a broad range of optical signal processing applications, including quantum computing, because of their capability to modify the phase or polarity of a photon stream by application of an electrical field. As the underlaying electro-optical Pockels effect is weak, a high electric field strength, to be provided by a RF control voltage of 500 V, is required for the modulation of the optical signal. To maximize the processing speed, the high voltage pulses must be applied with a repetition rate of 500 kHz. The trend towards higher data rates places greater demands on the Pockels cell drivers, which have to generate a stable high voltage and produce high-voltage pulses by fast switching. This paper focuses on the design of a suitable voltage driver circuit, using a non-conventional cascaded voltage-doubler circuit. It is proven by simulation and measurements that the use of the Karthaus-Fischer cascade is advantageous for providing the required high output currents.