Spectral control of nonclassical light using an integrated thin-film lithium niobate modulator

TL;DR

This paper demonstrates on-chip quantum spectral control of nonclassical light using a thin-film lithium niobate modulator, achieving high-frequency shifting and bandwidth compression for scalable quantum information processing.

Contribution

It introduces an integrated TFLN phase modulator capable of high-frequency shifting and bandwidth compression of nonclassical light, advancing scalable on-chip quantum spectral control.

Findings

Record-high electro-optic frequency shearing of ±641 GHz

Over eighteen-fold bandwidth compression of single photons

High visibility quantum interference between frequency-nondegenerate photons

Abstract

Manipulating the frequency and bandwidth of nonclassical light is essential for implementing frequency-encoded/multiplexed quantum computation, communication, and networking protocols, and for bridging spectral mismatch among various quantum systems. However, quantum spectral control requires a strong nonlinearity mediated by light, microwave, or acoustics, which is challenging to realize with high efficiency, low noise, and on an integrated chip. Here, we demonstrate both frequency shifting and bandwidth compression of nonclassical light using an integrated thin-film lithium niobate (TFLN) phase modulator. We achieve record-high electro-optic frequency shearing of telecom single photons over terahertz range ($\pm$ 641 GHz or $\pm$ 5.2 nm), enabling high visibility quantum interference between frequency-nondegenerate photon pairs. We further operate the modulator as a time lens and demonstrate over eighteen-fold (6.55 nm to 0.35 nm) bandwidth compression of single photons. Our results showcase the viability and promise of on-chip quantum spectral control for scalable photonic quantum information processing.