Study of an electro-optic modulator capable of generating simultaneous amplitude and phase modulations

TL;DR

This paper introduces a dual-electrode electro-optic modulator capable of generating tunable amplitude and phase modulations with high suppression, enabling versatile real-time optical modulation for various applications.

Contribution

The paper presents a novel universally tunable modulator with a geometric phase analysis, demonstrating its ability to produce various modulation states through electrical tuning.

Findings

Achieved relative suppressions of 38 dB, 39 dB, and 30 dB for different modulation types.

Device exhibits stable and continuous modulation tuning.

Potential applications include optical locking, single sideband modulation, and fast-switching.

Abstract

We report on the analysis and prototype-characterization of a dual-electrode electro-optic modulator that can generate both amplitude and phase modulations with a selectable relative phase, termed a universally tunable modulator (UTM). All modulation states can be reached by tuning only the electrical inputs, facilitating real-time tuning, and the device is shown to have good suppression and stability properties. A mathematical analysis is presented, including the development of a geometric phase representation for modulation. The experimental characterization of the device shows that relative suppressions of 38 dB, 39 dB and 30 dB for phase, single-sideband and carrier-suppressed modulations, respectively, can be obtained, as well as showing the device is well-behaved when scanning continuously through the parameter space of modulations. Uses for the device are discussed, including the tuning of lock points in optical locking schemes, single sideband applications, modulation fast-switching applications, and applications requiring combined modulations.