Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Quantum Correlations, Entanglement, and Squeezed States of Light in Kerr Optical Frequency Combs

Yanne K. Chembo

Published Dec 18, 2014• 3 citations
OpenAlex

Abstract

The dynamical behavior of Kerr optical frequency combs is very well understood today from the perspective of the semi-classical approximation. In this article, we provide a theoretical understanding of the phenomena of quantum correlations, multimode entanglement and squeezed states of light that can occur in these frequency combs when quantum noise is accounted for. We prove that for all stationary spatio-temporal patterns, the side-modes that are symmetrical relatively to the central (pumped) mode in the frequency domain display quantum correlations that can lead to squeezed states of light under some optimal conditions that are analytically determined. We show that these quantum correlations can persist regardless the dynamical state of the system (rolls or solitons), regardless of the spectral extension of the comb (number sidemodes), and regardless of the dispersion regime (normal or anomalous). We study with particular emphasis the two principal architectures for Kerr comb generation, namely the add-through and add-drop configurations. We show that in both cases, the ratio between out-coupling and total losses plays a key role as it directly determines the efficiency of the squeezing. We also explicitly determine the phase quadratures leading to photon entanglement, and analytically calculate their quantum noise spectra. The relevance of Kerr combs for quantum information systems at optical telecommunication wavelengths is also discussed.

Related papers

Quantum dynamics of Kerr optical frequency combs below and above threshold: Spontaneous four-wave mixing, entanglement, and squeezed states of light

Yanne K. Chembo

The dynamical behavior of Kerr optical frequency combs is very well understood today from the perspective of the semiclassical approximation. These combs are obtained by pumping an ultrahigh-$Q$ whispering-gallery mode resonator with a continuous-wave laser. The long-lifetime photons are trapped within the toruslike eigenmodes of the resonator, where they interact nonlinearly via the Kerr effect. In this article, we use quantum Langevin equations to provide a theoretical understanding of the nonclassical behavior of these combs when pumped below and above threshold. In the configuration where the system is under threshold, the pump field is the unique oscillating mode inside the resonator, and it triggers the phenomenon of spontaneous four-wave mixing, where two photons from the pump are symmetrically up- and down-converted in the Fourier domain. This phenomenon, also referred to as parametric fluorescence, can only be understood and analyzed from a fully quantum perspective as a consequence of the coupling between the field of the central (pumped) mode and the vacuum fluctuations of the various side modes. We analytically calculate the power spectra of the spontaneous emission noise, and we show that these spectra can be either single- or double-peaked depending on the value of the laser frequency, chromatic dispersion, pump power, and spectral distance between the central mode and the side mode of interest. We also calculate as well the overall spontaneous noise power per side mode and propose simplified analytical expressions for some particular cases. In the configuration where the system is pumped above threshold, we investigate the phenomena of quantum correlations and multimode squeezed states of light that can occur in the Kerr frequency combs originating from stimulated four-wave mixing. We show that for all stationary spatiotemporal patterns, the side modes that are symmetrical relative to the pumped mode in the frequency domain display quantum correlations that can lead to squeezed states of light under some optimal conditions that are analytically determined. These quantum correlations can persist regardless the dynamical state of the system (rolls or solitons), regardless of the spectral extension of the comb (number side modes) and regardless of the dispersion regime (normal or anomalous). We also explicitly determine the phase quadratures leading to photon entanglement and analytically calculate their quantum-noise spectra. For both the below- and above-threshold cases, we study with particular emphasis the two principal architectures for Kerr comb generation, namely the add-through and add-drop configurations. It is found that regardless of the configuration, an essential parameter is the ratio between out-coupling and total losses, which plays a key role as it directly determines the efficiency of the detected fluorescence or squeezing spectra. We finally discuss the relevance of Kerr combs for quantum information systems at optical telecommunication wavelengths below and above threshold.

arXiv:1412.5700•Physical Review A•Mar 10, 2016•135 citations

Long-range entanglement and quantum correlations in a multi-frequency comb system

Sahil Pontula, Debasmita Banerjee, Marin Soljacic +1 more

Frequency combs are multimode photonic systems that underlie countless precision sensing and metrology applications. Since their invention over two decades ago, numerous efforts have pushed frequency combs to broader bandwidths and more stable operation. More recently, quantum squeezing and entanglement have been explored in single frequency comb systems for quantum advantages in sensing and signal multiplexing. However, the production of quantum light across multiple frequency combs remains unexplored. In this work, we theoretically explore a mechanism that generates a series of nonlinearly coupled frequency combs through cascaded three-wave upconversion and downconversion processes mediated by a single idler comb. We show how this system generates inter- and intracomb two-mode squeezing and entanglement spanning a very large spectral range, from ultraviolet to mid-IR frequencies. Finally, we show how this system can be engineered to produce on-demand multimode quantum light through covariance matrix optimization. Our findings could enable tunable broadband ghost spectroscopy protocols, squeezing-enhanced pump-probe measurements, and broadband entanglement between spectrally-multiplexed quanta of information.

quant-pharXiv:2511.13604•Nov 18, 2025•0 citations

Quantum phenomena in ultra-highQwhispering gallery mode resonators and applications to quantum information systems

Yanne K. Chembo

Kerr optical frequency combs are obtained by pumping an ultra-high Q whispering-gallery mode resonator with a continuous-wave laser. Here, we use quantum Langevin equations to investigate the non-classical behavior of these combs when pumped below and above threshold. Under threshold, we study the phenomenon of spontaneous four-wave mixing, while above threshold, we investigate the phenomenon of two-mode squeezing. For both the below- and above-threshold cases, we find that an essential parameter is the ratio between out-coupling and total losses, which directly determines the efficiency of the detected spontaneous noise or squeezing spectra.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Mar 16, 2016•0 citations

Quantum and classical noise characteristics of parametrically driven cavity solitons in dispersive Kerr resonators

Sophie S. Shamailov, Miro Erkintalo

Temporal cavity solitons generated in monochromatically driven dispersive Kerr resonators offer an attractive avenue for on-chip optical frequency comb generation. Key to many of their applications is to understand how noise -- both technical and quantum -- affects the soliton states, which has accordingly been extensively investigated. Here, we report on a comprehensive theoretical study that elucidates how technical and quantum fluctuations impact a new type of soliton structure that has very recently been predicted and observed in dispersive Kerr resonators under conditions of bichromatic driving: the pure-Kerr parametrically driven cavity soliton (PDCS). We examine how classical laser phase noise transfers from the two pump fields onto the soliton frequency comb, and we calculate the solitons' fundamental quantum-limited timing jitter and two-mode squeezing spectra. In each case, we find that PDCSs can out-perform conventional cavity solitons with comparable characteristics, even when driven by two uncorrelated lasers. Our results demonstrate that pure-Kerr PDCSs can offer unprecedented performance in noise-sensitive photonic applications and as a quantum resource

physics.opticsCross-listedarXiv:2605.29321•Physical Review Letters•May 29, 2026•0 citations

Quantum states of Kerr combs and why solitons are strongly squeezed

Melissa A. Guidry, Jelena Vuckovic A

Below-threshold signal-idler quantum Kerr combs are the most explored quantum Kerr state to-date, both for fundamental study and application in quantum technologies. However, after the first onset of optical parametric oscillation, the connectivity of the below-threshold modes grows in complexity as modes which were once purely populated with spontaneous photons develop comparatively strong mean fields which drive correlations themselves. In this talk, I will describe numeric and experimental study of this second class of states, with a focus on quantum correlations and quadrature squeezing as tools for understanding classical nonlinear optics.

Quantum Computing, Communication, and Simulation•Mar 13, 2024•0 citations

Quantum correlations in integrated photonic frequency combs

Laurent Labonté, Adrien Bensemhoun, Dorian Oser +12 more

Integrated photonic platforms provide a powerful route toward scalable and stable quantum light sources. In this presentation, we explore how quantum correlations can be generated, distributed, and characterized in the frequency domain using integrated photonic frequency combs. Relying on Kerr nonlinear microresonators operated below and above threshold, we demonstrate the generation of discrete entangled photon pairs as well as bright multipartite quantum states involving many spectral modes. We show how frequency multiplexing enables both multi-user quantum communication and enhanced data rates, while remaining fully compatible with integrated photonic circuits. Beyond bipartite entanglement, we report direct signatures of genuine multipartite quantum correlations in bright frequency combs. These results highlight integrated photonics as a versatile and scalable platform for multimode quantum technologies in communication, sensing, and metrology.

Integrated Photonics Platforms•May 29, 2026•0 citations
The dynamical behavior of Kerr optical frequency combs is very well understood today from the perspective of the semi-classical approximation. In this article, we provide a theoretical understanding of the phenomena of quantum correlations, multimode entanglement and squeezed states of light that can occur in these frequency combs when quantum noise is accounted for. We prove that for all stationary spatio-temporal patterns, the side-modes that are symmetrical relatively to the central (pumped) mode in the frequency domain display quantum correlations that can lead to squeezed states of light under some optimal conditions that are analytically determined. We show that these quantum correlations can persist regardless the dynamical state of the system (rolls or solitons), regardless of the spectral extension of the comb (number sidemodes), and regardless of the dispersion regime (normal or anomalous). We study with particular emphasis the two principal architectures for Kerr comb generation, namely the add-through and add-drop configurations. We show that in both cases, the ratio between out-coupling and total losses plays a key role as it directly determines the efficiency of the squeezing. We also explicitly determine the phase quadratures leading to photon entanglement, and analytically calculate their quantum noise spectra. The relevance of Kerr combs for quantum information systems at optical telecommunication wavelengths is also discussed.
The dynamical behavior of Kerr optical frequency combs is very well understood today from the perspective of the semiclassical approximation. These combs are obtained by pumping an ultrahigh-QQQ whispering-gallery mode resonator with a continuous-wave laser. The long-lifetime photons are trapped within the toruslike eigenmodes of the resonator, where they interact nonlinearly via the Kerr effect. In this article, we use quantum Langevin equations to provide a theoretical understanding of the nonclassical behavior of these combs when pumped below and above threshold. In the configuration where the system is under threshold, the pump field is the unique oscillating mode inside the resonator, and it triggers the phenomenon of spontaneous four-wave mixing, where two photons from the pump are symmetrically up- and down-converted in the Fourier domain. This phenomenon, also referred to as parametric fluorescence, can only be understood and analyzed from a fully quantum perspective as a consequence of the coupling between the field of the central (pumped) mode and the vacuum fluctuations of the various side modes. We analytically calculate the power spectra of the spontaneous emission noise, and we show that these spectra can be either single- or double-peaked depending on the value of the laser frequency, chromatic dispersion, pump power, and spectral distance between the central mode and the side mode of interest. We also calculate as well the overall spontaneous noise power per side mode and propose simplified analytical expressions for some particular cases. In the configuration where the system is pumped above threshold, we investigate the phenomena of quantum correlations and multimode squeezed states of light that can occur in the Kerr frequency combs originating from stimulated four-wave mixing. We show that for all stationary spatiotemporal patterns, the side modes that are symmetrical relative to the pumped mode in the frequency domain display quantum correlations that can lead to squeezed states of light under some optimal conditions that are analytically determined. These quantum correlations can persist regardless the dynamical state of the system (rolls or solitons), regardless of the spectral extension of the comb (number side modes) and regardless of the dispersion regime (normal or anomalous). We also explicitly determine the phase quadratures leading to photon entanglement and analytically calculate their quantum-noise spectra. For both the below- and above-threshold cases, we study with particular emphasis the two principal architectures for Kerr comb generation, namely the add-through and add-drop configurations. It is found that regardless of the configuration, an essential parameter is the ratio between out-coupling and total losses, which plays a key role as it directly determines the efficiency of the detected fluorescence or squeezing spectra. We finally discuss the relevance of Kerr combs for quantum information systems at optical telecommunication wavelengths below and above threshold.
Frequency combs are multimode photonic systems that underlie countless precision sensing and metrology applications. Since their invention over two decades ago, numerous efforts have pushed frequency combs to broader bandwidths and more stable operation. More recently, quantum squeezing and entanglement have been explored in single frequency comb systems for quantum advantages in sensing and signal multiplexing. However, the production of quantum light across multiple frequency combs remains unexplored. In this work, we theoretically explore a mechanism that generates a series of nonlinearly coupled frequency combs through cascaded three-wave upconversion and downconversion processes mediated by a single idler comb. We show how this system generates inter- and intracomb two-mode squeezing and entanglement spanning a very large spectral range, from ultraviolet to mid-IR frequencies. Finally, we show how this system can be engineered to produce on-demand multimode quantum light through covariance matrix optimization. Our findings could enable tunable broadband ghost spectroscopy protocols, squeezing-enhanced pump-probe measurements, and broadband entanglement between spectrally-multiplexed quanta of information.
Kerr optical frequency combs are obtained by pumping an ultra-high Q whispering-gallery mode resonator with a continuous-wave laser. Here, we use quantum Langevin equations to investigate the non-classical behavior of these combs when pumped below and above threshold. Under threshold, we study the phenomenon of spontaneous four-wave mixing, while above threshold, we investigate the phenomenon of two-mode squeezing. For both the below- and above-threshold cases, we find that an essential parameter is the ratio between out-coupling and total losses, which directly determines the efficiency of the detected spontaneous noise or squeezing spectra.
Temporal cavity solitons generated in monochromatically driven dispersive Kerr resonators offer an attractive avenue for on-chip optical frequency comb generation. Key to many of their applications is to understand how noise -- both technical and quantum -- affects the soliton states, which has accordingly been extensively investigated. Here, we report on a comprehensive theoretical study that elucidates how technical and quantum fluctuations impact a new type of soliton structure that has very recently been predicted and observed in dispersive Kerr resonators under conditions of bichromatic driving: the pure-Kerr parametrically driven cavity soliton (PDCS). We examine how classical laser phase noise transfers from the two pump fields onto the soliton frequency comb, and we calculate the solitons' fundamental quantum-limited timing jitter and two-mode squeezing spectra. In each case, we find that PDCSs can out-perform conventional cavity solitons with comparable characteristics, even when driven by two uncorrelated lasers. Our results demonstrate that pure-Kerr PDCSs can offer unprecedented performance in noise-sensitive photonic applications and as a quantum resource
Below-threshold signal-idler quantum Kerr combs are the most explored quantum Kerr state to-date, both for fundamental study and application in quantum technologies. However, after the first onset of optical parametric oscillation, the connectivity of the below-threshold modes grows in complexity as modes which were once purely populated with spontaneous photons develop comparatively strong mean fields which drive correlations themselves. In this talk, I will describe numeric and experimental study of this second class of states, with a focus on quantum correlations and quadrature squeezing as tools for understanding classical nonlinear optics.
Integrated photonic platforms provide a powerful route toward scalable and stable quantum light sources. In this presentation, we explore how quantum correlations can be generated, distributed, and characterized in the frequency domain using integrated photonic frequency combs. Relying on Kerr nonlinear microresonators operated below and above threshold, we demonstrate the generation of discrete entangled photon pairs as well as bright multipartite quantum states involving many spectral modes. We show how frequency multiplexing enables both multi-user quantum communication and enhanced data rates, while remaining fully compatible with integrated photonic circuits. Beyond bipartite entanglement, we report direct signatures of genuine multipartite quantum correlations in bright frequency combs. These results highlight integrated photonics as a versatile and scalable platform for multimode quantum technologies in communication, sensing, and metrology.