# Reconfigurable re-entrant cavity for wireless coupling to an electro-optomechanical device

## TL;DR

This paper introduces a reconfigurable 3D microwave cavity for an electro-optomechanical converter, enhancing tunability and optical performance while maintaining low loss, crucial for quantum network applications.

## Contribution

It presents a novel 3D microwave cavity design that simplifies optical assembly and allows flexible tuning without affecting electromechanical experiments.

## Key findings

- Flexible microwave coupling tuning achieved
- Optical performance improved with high-finesse cavity compatibility
- Electromechanical experiments unaffected by the new cavity design

## Abstract

An electro-optomechanical device capable of microwave-to-optics conversion has recently been demonstrated, with the vision of enabling optical networks of superconducting qubits. Here we present an improved converter design that uses a three-dimensional (3D) microwave cavity for coupling between the microwave transmission line and an integrated LC resonator on the converter chip. The new design simplifies the optical assembly and decouples it from the microwave part of the setup. Experimental demonstrations show that the modular device assembly allows us to flexibly tune the microwave coupling to the converter chip while maintaining small loss. We also find that electromechanical experiments are not impacted by the additional microwave cavity. Our design is compatible with a high-finesse optical cavity and will improve optical performance.