Highly squeezed nanophotonic quantum microcombs with broadband frequency tunability
Abstract
Squeezed light offers genuine quantum advantage in enhanced sensing and quantum computation; yet the level of squeezing or quantum noise reduction generated from nanophotonic chips has been limited. In addition to strong quantum noise reduction, key desiderata for such a nanophotonic squeezer include frequency agility or tunability over a broad frequency range, and simultaneous operation in many distinct, well-defined quantum modes (qumodes). Here we present a strongly overcoupled silicon nitride squeezer based on a below-threshold optical parametric amplifier (OPA) that produces directly detected squeezing of 5.6 dB 0.2 dB, surpassing previous demonstrations in both continuous-wave and pulsed regimes. We introduce a seed-assisted detection technique into such nanophotonic squeezers that reveals a quantum frequency comb (QFC) of 16 qumodes, with a separation of 11~THz between the furthest qumode pair, while maintaining a strong squeezing. Additionally, we report spectral tuning of a qumode comb pair over one free-spectral range of the OPA, thus bridging the spacing between the discrete modes of the QFC. Our results significantly advance both the generation and detection of nanophotonic squeezed light in a broadband and multimode platform, establishing a scalable, chip-integrated path for compact quantum sensors and continuous-variable quantum information processing systems.
Cite
@article{arxiv.2505.03734,
title = {Highly squeezed nanophotonic quantum microcombs with broadband frequency tunability},
author = {Yichen Shen and Ping-Yen Hsieh and Dhruv Srinivasan and Antoine Henry and Gregory Moille and Sashank Kaushik Sridhar and Alessandro Restelli and You-Chia Chang and Kartik Srinivasan and Thomas A. Smith and Avik Dutt},
journal= {arXiv preprint arXiv:2505.03734},
year = {2025}
}