Reconfigurable photonics on a glass chip

TL;DR

This paper presents a femtosecond laser-written, reconfigurable 4x4 multiport interferometer on a glass chip, enabling fast switching and programmable linear-optical circuits for quantum computing applications.

Contribution

It demonstrates a universal, reconfigurable integrated photonic device with record-fast switching time, advancing quantum optical experiments with femtosecond laser-written circuits.

Findings

Achieved a switching time of ~10 ms for the interferometer.

Implemented a 4x4 multiport interferometer with 12 thermooptical phase shifters.

Analyzed the reconfigurability and potential improvements for quantum optical experiments.

Abstract

Reconfigurability of integrated photonic chips plays a key role in current experiments in the area of linear-optical quantum computing. We demonstrate a reconfigurable multiport interferometer implemented as a femtosecond laser-written integrated photonic device. The device includes a femtosecond laser-written $4\times 4$ multiport interferometer equipped with 12 thermooptical phase shifters, making it a universal programmable linear-optical circuit. We achieve a record fast switching time for a single nested Mach-Zender interferometer of $\sim10$ ms and quantitatively analyse the reconfigurability of the optical circuit. We believe, that our results will improve the current state of quantum optical experiments utilizing femtosecond laser-written photonic circuits.