Integrated Photonic Sensing

TL;DR

This paper discusses a modular integrated photonics platform for quantum sensing, focusing on loss mitigation, source optimization, programmable circuits, and state tomography to enhance optical phase estimation.

Contribution

It introduces methods for loss-tolerant quantum states, optimized photon sources, programmable photonic circuits, and lossy state tomography, advancing integrated photonic quantum sensing technologies.

Findings

Loss-tolerant Holland-Burnett states improve phase estimation accuracy

Optimized spontaneous four-wave mixing sources yield high-purity photons

Programmable circuits compensate for fabrication imperfections

Abstract

Loss is a critical roadblock to achieving photonic quantum-enhanced technologies. We explore a modular platform for implementing integrated photonics experiments and consider the effects of loss at different stages of these experiments, including state preparation, manipulation and measurement. We frame our discussion mainly in the context of quantum sensing and focus particularly on the use of loss-tolerant Holland-Burnett states for optical phase estimation. In particular, we discuss spontaneous four-wave mixing in standard birefringent fibre as a source of pure, heralded single photons and present methods of optimising such sources. We also outline a route to programmable circuits which allow the control of photonic interactions even in the presence of fabrication imperfections and describe a ratiometric characterisation method for beam splitters which allows the characterisation of complex circuits without the need for full process tomography. Finally, we present a framework for performing state tomography on heralded states using lossy measurement devices. This is motivated by a calculation of the effects of fabrication imperfections on precision measurement using Holland-Burnett states.