Multicolor continuous-variable quantum entanglement in the Kerr frequency comb

TL;DR

This paper investigates the quantum entanglement properties of dissipative Kerr solitons in microresonator frequency combs, revealing their potential for quantum networking and sensing.

Contribution

It uncovers the quantum features and entanglement characteristics of Kerr frequency combs, especially the spectral edge entanglement and entanglement disappearance at the spectrum center.

Findings

Entanglement occurs at the spectral edges due to photon-pair generation.

Quantum entanglement disappears at the spectrum center due to self-locking phenomena.

Dissipative Kerr solitons exhibit significant quantum features relevant for quantum technologies.

Abstract

In a traveling wave microresonator, the cascaded four-wave mixing (FWM) between optical modes allows the generation of frequency combs, including intriguing dissipative Kerr solitons (DKS). In this study, we explore the quantum fluctuations of frequency combs and unveil the quantum features of solitons. The entanglement of DKS exhibits two distinct characteristics. For modes located at the spectral edge with a small number of excitations, different comb modes with multiple colors become entangled due to photon-pair generation and coherent photon conversion stimulated by the FWM. Notably, we observe a sudden disappearance of quantum entanglement in the center of the DKS spectrum, which is attributed to the self-locking phenomena in the FWM network. Our findings demonstrate the prominent quantum nature of DKS, which is of fundamental significance in quantum optics and has the potential to be utilized in quantum networking and distributed quantum sensing applications.