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

arXiv:2309.01181 · Physical Review Applied

Polarization-entangled quantum frequency comb from a silicon nitride microring resonator

Wenjun Wen, Wenhan Yan, Chi Lu, Liangliang Lu, Wu Xiaoyu, Yanqing Lu, Shining N. Zhu, Xiao‐Song Ma

Published Dec 18, 2023• 30 citations
arXivHTMLPDF

Abstract

Integrated microresonator facilitates the realization of quantum frequency comb (QFC), which provides a large number of discrete frequency modes with broadband spectral range and narrow linewidth. However, all previous demonstrations have focused on the generation of energy-time or time-bin entangled photons from QFC. Realizing polarization-entangled quantum frequency comb, which is a useful resource for the fundamental study of quantum mechanics and quantum information applications, remains challenging. Here, we demonstrate a broadband polarization-entangled quantum frequency comb by combining an integrated silicon-nitride microresonator with a Sagnac interferometer. With a free spectral range of about 99 GHz and a narrow linewidth of about 190 MHz, our source provides 22 polarization-entangled photon pairs with frequency covering the whole telecom C-band. The entanglement fidelities for all 22 pairs are above 81%, including 17 pairs with fidelities higher than 90%. Our demonstration paves the way for employing the polarization-entangled quantum frequency comb in quantum network using CMOS technology as well as standard dense wavelength division-multiplexing technology.

DOI
10.1103/physrevapplied.20.064032

Related papers

Platform for designing bipartite entangled quantum frequency combs based on silicon nitride microring resonators

Nianqin Li, Bo Ji, Yang Shen +1 more

Integrated Kerr quantum frequency combs (QFCs), with the potential to generate multiple and scalable quantum states, have emerged as a compact, stable, and fundamental resource for broadband entanglement. Here, we build a platform for designing bipartite entangled QFCs via an on-chip silicon nitride microring resonator. By establishing the system quantum dynamics of Kerr nonlinear microresonators, our platform can support up to 12 continuous-variable quantum modes, in the form of six simultaneously two-mode squeezed pairs under the influence of hysteresis. The entanglement degree of frequency-mode pairs is dependent on the resonator structure and ambient temperature. By adjusting the cavity temperature, we can optimize the performance of entanglement under certain injected pump power and pump detuning. Our comprehensive QFC designing process and entanglement distribution control may ameliorate the generation and optimization of entanglement.

Physical Review Applied•May 29, 2024•7 citations

Discrete and Parallel Frequency‐Bin Entanglement Generation from Quantum Frequency Comb

Chi Lu, Wu Xiaoyu, Wenjun Wen +1 more

Abstract Photons’ frequency degree of freedom is promising to realize large‐scale quantum information processing. Quantum frequency combs (QFCs) generated in integrated nonlinear microresonators can produce multiple frequency modes with narrow linewidth. Here, polarization‐entangled QFCs are utilized to generate discrete frequency‐bin entangled states. Fourteen pairs of polarization‐entangled photons with different frequencies are simultaneously transformed into frequency‐bin entangled states. The characteristic of frequency‐bin entanglement is demonstrated by Hong‐Ou‐Mandel interference, which can be performed with single or multiple frequency pairs in parallel. This work paves the way for harnessing large‐scale frequency‐bin entanglement and converting between different degrees of freedom in quantum information processing.

arXiv:2411.18304•Advanced Quantum Technologies•Nov 5, 2024•2 citations

A bright polarization-entangled photon pair source based on silicon photonics integration

Xin Hua, Yan Xu, Lu Tie Xu +6 more

Developing a high-quality, bright source of polarization-entangled photon pairs on CMOS-compatible integrated platforms, such as silicon or silicon nitride, remains a significant challenge. Here, a novel silicon chip-based nonlinear Sagnac interferometer, which mainly integrates a bidirectionally pumped microring resonator with a polarization-splitting rotator, was proposed to generate polarization-entangled photon pairs. By pumping the system with a pulsed laser at 1550 nm and a power of 78 μW, polarization-entangled photon pairs in the telecom C-band were produced through spontaneous four-wave mixing, achieving a state-of-the-art brightness of 1.6 × 107 pairs s−1 GHz−1 mW−2. Using an off-chip polarization analyzer, the visibility of polarization-correlation interference fringe was measured to be 96.6%. Quantum state tomography revealed a fidelity of 0.958 for the maximally entangled state produced by the source. These exceptional performance metrics, combined with the integrability of the device, make it highly suitable for advanced quantum applications, particularly in multi-user entanglement-based quantum communication networks.

APL Photonics•Jun 1, 2025•4 citations

Efficient and broadband quantum frequency comb generation in a monolithic AlGaAs-on-insulator microresonator

Xiaodong Zheng, Xu Jing, Chenbo Liu +9 more

The exploration of photonic systems for quantum information processing has generated widespread interest in multiple cutting-edge research fields. Photonic frequency encoding stands out as an especially viable approach, given its natural alignment with established optical communication technologies, including fiber networks and wavelength-division multiplexing systems. Substantial reductions in hardware resources and improvements in quantum performance can be expected by utilizing multiple frequency modes. The integration of nonlinear photonics with microresonators provides a compelling way for generating frequency-correlated photon pairs across discrete spectral modes. Here, by leveraging the high material nonlinearity and low nonlinear loss, we demonstrate an efficient chip-scale multi-wavelength quantum light source based on AlGaAs-on-insulator, featuring a free spectral range of approximately 200 GHz at telecom wavelengths. The optimized submicron waveguide geometry provides both high effective nonlinearity (~550 m$^{-1}$W$^{-1}$) and broad generation bandwidth, producing eleven distinct wavelength pairs across a 35.2 nm bandwidth with an average spectral brightness of 2.64 GHz mW$^{-2}$nm$^{-1}$. The generation of energy-time entanglement for each pair of frequency modes is verified through Franson interferometry, yielding an average net visibility of 93.1%. With its exceptional optical gain and lasing capabilities, the AlGaAs-on-insulator platform developed here shows outstanding potential for realizing fully integrated, ready-to-deploy quantum photonic systems on chip.

quant-pharXiv:2601.08289•Jan 14, 2026•0 citations

50-Ghz-Spaced Comb of High-Dimensional Frequency-Bin Entangled Photons from an On-Chip Silicon Nitride Microresonator

Poolad Imany, Jaramillo-Villegas,, Jose A., Ogaga D. Odele +6 more

Quantum frequency combs from chip-scale integrated sources are promising candidates for scalable and robust quantum information processing (QIP). However, to use these quantum combs for frequency domain QIP, demonstration of entanglement in the frequency basis, showing that the entangled photons are in a coherent superposition of multiple frequency bins, is required. We present a verification of qubit and qutrit frequency-bin entanglement using an on-chip quantum frequency comb with 40 mode pairs, through a two-photon interference measurement that is based on electro-optic phase modulation. Our demonstrations provide an important contribution in establishing integrated optical microresonators as a source for high-dimensional frequency-bin encoded quantum computing, as well as dense quantum key distribution.

•Jan 1, 2018•168 citations

50-GHz-spaced comb of high-dimensional frequency-bin entangled photons from an on-chip silicon nitride microresonator

Poolad Imany, Jose A. Jaramillo-Villegas, Ogaga D. Odele +6 more

Quantum frequency combs from chip-scale integrated sources are promising candidates for scalable and robust quantum information processing (QIP). However, to use these quantum combs for frequency domain QIP, demonstration of entanglement in the frequency basis, showing that the entangled photons are in a coherent superposition of multiple frequency bins, is required. We present a verification of qubit and qutrit frequency-bin entanglement using an on-chip quantum frequency comb with 40 mode pairs, through a two-photon interference measurement that is based on electro-optic phase modulation. Our demonstrations provide an important contribution in establishing integrated optical microresonators as a source for high-dimensional frequency-bin encoded quantum computing, as well as dense quantum key distribution.

arXiv:1707.02276•Optics Express•Jan 18, 2018•185 citations
Integrated microresonator facilitates the realization of quantum frequency comb (QFC), which provides a large number of discrete frequency modes with broadband spectral range and narrow linewidth. However, all previous demonstrations have focused on the generation of energy-time or time-bin entangled photons from QFC. Realizing polarization-entangled quantum frequency comb, which is a useful resource for the fundamental study of quantum mechanics and quantum information applications, remains challenging. Here, we demonstrate a broadband polarization-entangled quantum frequency comb by combining an integrated silicon-nitride microresonator with a Sagnac interferometer. With a free spectral range of about 99 GHz and a narrow linewidth of about 190 MHz, our source provides 22 polarization-entangled photon pairs with frequency covering the whole telecom C-band. The entanglement fidelities for all 22 pairs are above 81%, including 17 pairs with fidelities higher than 90%. Our demonstration paves the way for employing the polarization-entangled quantum frequency comb in quantum network using CMOS technology as well as standard dense wavelength division-multiplexing technology.
Integrated Kerr quantum frequency combs (QFCs), with the potential to generate multiple and scalable quantum states, have emerged as a compact, stable, and fundamental resource for broadband entanglement. Here, we build a platform for designing bipartite entangled QFCs via an on-chip silicon nitride microring resonator. By establishing the system quantum dynamics of Kerr nonlinear microresonators, our platform can support up to 12 continuous-variable quantum modes, in the form of six simultaneously two-mode squeezed pairs under the influence of hysteresis. The entanglement degree of frequency-mode pairs is dependent on the resonator structure and ambient temperature. By adjusting the cavity temperature, we can optimize the performance of entanglement under certain injected pump power and pump detuning. Our comprehensive QFC designing process and entanglement distribution control may ameliorate the generation and optimization of entanglement.
Abstract Photons’ frequency degree of freedom is promising to realize large‐scale quantum information processing. Quantum frequency combs (QFCs) generated in integrated nonlinear microresonators can produce multiple frequency modes with narrow linewidth. Here, polarization‐entangled QFCs are utilized to generate discrete frequency‐bin entangled states. Fourteen pairs of polarization‐entangled photons with different frequencies are simultaneously transformed into frequency‐bin entangled states. The characteristic of frequency‐bin entanglement is demonstrated by Hong‐Ou‐Mandel interference, which can be performed with single or multiple frequency pairs in parallel. This work paves the way for harnessing large‐scale frequency‐bin entanglement and converting between different degrees of freedom in quantum information processing.
Developing a high-quality, bright source of polarization-entangled photon pairs on CMOS-compatible integrated platforms, such as silicon or silicon nitride, remains a significant challenge. Here, a novel silicon chip-based nonlinear Sagnac interferometer, which mainly integrates a bidirectionally pumped microring resonator with a polarization-splitting rotator, was proposed to generate polarization-entangled photon pairs. By pumping the system with a pulsed laser at 1550 nm and a power of 78 μW, polarization-entangled photon pairs in the telecom C-band were produced through spontaneous four-wave mixing, achieving a state-of-the-art brightness of 1.6 × 107 pairs s−1 GHz−1 mW−2. Using an off-chip polarization analyzer, the visibility of polarization-correlation interference fringe was measured to be 96.6%. Quantum state tomography revealed a fidelity of 0.958 for the maximally entangled state produced by the source. These exceptional performance metrics, combined with the integrability of the device, make it highly suitable for advanced quantum applications, particularly in multi-user entanglement-based quantum communication networks.
The exploration of photonic systems for quantum information processing has generated widespread interest in multiple cutting-edge research fields. Photonic frequency encoding stands out as an especially viable approach, given its natural alignment with established optical communication technologies, including fiber networks and wavelength-division multiplexing systems. Substantial reductions in hardware resources and improvements in quantum performance can be expected by utilizing multiple frequency modes. The integration of nonlinear photonics with microresonators provides a compelling way for generating frequency-correlated photon pairs across discrete spectral modes. Here, by leveraging the high material nonlinearity and low nonlinear loss, we demonstrate an efficient chip-scale multi-wavelength quantum light source based on AlGaAs-on-insulator, featuring a free spectral range of approximately 200 GHz at telecom wavelengths. The optimized submicron waveguide geometry provides both high effective nonlinearity (~550 m−1^{-1}−1W−1^{-1}−1) and broad generation bandwidth, producing eleven distinct wavelength pairs across a 35.2 nm bandwidth with an average spectral brightness of 2.64 GHz mW−2^{-2}−2nm−1^{-1}−1. The generation of energy-time entanglement for each pair of frequency modes is verified through Franson interferometry, yielding an average net visibility of 93.1%. With its exceptional optical gain and lasing capabilities, the AlGaAs-on-insulator platform developed here shows outstanding potential for realizing fully integrated, ready-to-deploy quantum photonic systems on chip.
Quantum frequency combs from chip-scale integrated sources are promising candidates for scalable and robust quantum information processing (QIP). However, to use these quantum combs for frequency domain QIP, demonstration of entanglement in the frequency basis, showing that the entangled photons are in a coherent superposition of multiple frequency bins, is required. We present a verification of qubit and qutrit frequency-bin entanglement using an on-chip quantum frequency comb with 40 mode pairs, through a two-photon interference measurement that is based on electro-optic phase modulation. Our demonstrations provide an important contribution in establishing integrated optical microresonators as a source for high-dimensional frequency-bin encoded quantum computing, as well as dense quantum key distribution.
Quantum frequency combs from chip-scale integrated sources are promising candidates for scalable and robust quantum information processing (QIP). However, to use these quantum combs for frequency domain QIP, demonstration of entanglement in the frequency basis, showing that the entangled photons are in a coherent superposition of multiple frequency bins, is required. We present a verification of qubit and qutrit frequency-bin entanglement using an on-chip quantum frequency comb with 40 mode pairs, through a two-photon interference measurement that is based on electro-optic phase modulation. Our demonstrations provide an important contribution in establishing integrated optical microresonators as a source for high-dimensional frequency-bin encoded quantum computing, as well as dense quantum key distribution.