Compact arbitrary optical waveform modulator with digital feedback

A key requirement for quantum technologies based on atoms, ions, and molecules is the ability to realize precise phase- and amplitude-controlled quantum operations via coherent laser pulses. However, for generating pulses on the submicrosecond timescale, the characteristics of the optical and electronic components can introduce unwanted distortions that have a detrimental effect on the fidelity of quantum operations. In this paper, we present a compact arbitrary optical waveform modulator that integrates a double-pass acousto-optic modulator for user-specified laser amplitude and phase modulations. Additionally, the module integrates an optical heterodyne detector to extract the precise laser pulse shape in real time. The measured pulse shape is then fed into a digital feedback loop used to estimate the complex-valued transfer function and predistorted input pulses. We demonstrate the performance by generating shaped laser pulses suitable for realizing quantum logic gates with durations down to 180 ns, requiring only a small number of feedback iterations.