# Coherent Magneto-Optomechanical Signal Transduction and Long-Distance Phase-Shift Keying

## TL;DR

This paper introduces a magnetically-mediated optomechanical transducer capable of converting microwave quantum information into optical signals, enabling high-bandwidth, low-power classical communication, and potentially quantum-level signal transduction.

## Contribution

It presents a novel magneto-optomechanical wavelength conversion technique that functions as a coherent optical modulator and supports quantum-level signal transduction.

## Key findings

- Achieved encoding of three bits of information simultaneously.
- Successfully transmitted a 52,500 pixel image over 6 km fiber with 0.67% error.
- Demonstrated quantum description viability of the transduction process.

## Abstract

A transducer capable of converting quantum information stored as microwaves into telecom-wavelength signals is a critical piece of future quantum technology as it promises to enable the networking of quantum processors. Cavity optomechanical devices that are simultaneously coupled to microwave fields and optical resonances are being pursued in this regard. Yet even in the classical regime, developing optical modulators based on cavity optomechanics could provide lower power or higher bandwidth alternatives to current technology. Here we demonstrate a magnetically-mediated wavelength conversion technique, based on mixing high frequency tones with an optomechanical torsional resonator. This process can act either as an optical phase or amplitude modulator depending on the experimental configuration, and the carrier modulation is always coherent with the input tone. Such coherence allows classical information transduction and transmission via the technique of phase-shift keying. We demonstrate that we can encode up to eight bins of information, corresponding to three bits, simultaneously and demonstrate the transmission of an 52,500 pixel image over 6 km of optical fiber with just 0.67% error. Furthermore, we show that magneto-optomechanical transduction can be described in a fully quantum manner, implying that this is a viable approach to signal transduction at the single quantum level.