A squeezed quantum microcomb on a chip

TL;DR

This paper demonstrates a chip-integrated quantum microcomb with 40 entangled modes and 1.6 dB squeezing, opening new possibilities for quantum computing, networking, and spectroscopy.

Contribution

It presents the first deterministic quantum microcomb on a chip, featuring 40 entangled modes and high-resolution characterization.

Findings

40 quantum modes observed within 1 THz span

Maximum raw squeezing of 1.6 dB achieved

High-resolution spectroscopy confirms frequency equidistance

Abstract

The optical microresonator-based frequency comb (microcomb) provides a versatile platform for nonlinear physics studies and has wide applications ranging from metrology to spectroscopy. Deterministic quantum regime is an unexplored aspect of microcombs, in which unconditional entanglements among hundreds of equidistant frequency modes can serve as critical ingredients to scalable universal quantum computing and quantum networking. Here, we demonstrate a deterministic quantum microcomb in a silica microresonator on a silicon chip. 40 continuous-variable quantum modes, in the form of 20 simultaneously two-mode squeezed comb pairs, are observed within 1 THz optical span at telecommunication wavelengths. A maximum raw squeezing of 1.6 dB is attained. A high-resolution spectroscopy measurement is developed to characterize the frequency equidistance of quantum microcombs. Our demonstration offers the possibility to leverage deterministically generated, frequency multiplexed quantum states and integrated photonics to open up new avenues in fields of spectroscopy, quantum metrology, and scalable quantum information processing.