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arXiv · 2508.20454

Modulation Instability-Induced Multimode Squeezing in Quadratic Frequency Combs

Haodong Xu·Nianqin Li·Zijun Shu·Yang Shen·Bo Ji·Aiping Xie·Feng Yang·Dengcai Yang·Jing Peng·Hang Gong·Guoxiang Huang·Chunbo Zhao·Wei Li·Tengfei Wu·Guangqiang He
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Abstract

Lithium niobate (LN) microring resonators, characterized by an exceptionally high second-order nonlinear coefficient and superior electro-optic tunability, serve as an outstanding platform for the precise control of integrated quantum frequency combs (QFCs). In this study, we introduce a bipartite entanglement criterion to investigate the pairwise entanglement characteristics of QFCs generated via the spontaneous parametric down-conversion (SPDC) process in lithium niobate microring resonators operating below threshold. Furthermore, we propose a universal framework for analyzing multimode squeezing in quadratic frequency combs, enabling the realization of ultrabroadband and high-degree multimode squeezing. We further reveal the underlying physical mechanism: modulation instability (MI), regulated by temporal walk-off control, not only enables the formation of frequency combs but also induces multimode squeezing in the corresponding resonant modes. This study uncovers the previously unexplored role of on-chip multimode squeezing in quadratic frequency combs while facilitating collective noise suppression across multiple modes, thus holding substantial potential for advancing quantum precision measurement and quantum information processing.

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Haodong Xu, Nianqin Li, Zijun Shu, Yang Shen, Bo Ji, Aiping Xie, Feng Yang, Dengcai Yang, Jing Peng, Hang Gong, Guoxiang Huang, Chunbo Zhao, Wei Li, Tengfei Wu, Guangqiang He. 2025-08-28. Modulation Instability-Induced Multimode Squeezing in Quadratic Frequency Combs. https://arxiv.org/abs/2508.20454

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