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:2112.14009 · Optics Letters

Spectrally pure photon pair generation in asymmetric heterogeneously coupled waveguides

Xiangyan Ding, Jing Ma, Liying Tan, Amr Saher Helmy, Dongpeng Kang

Published May 26, 2021• 1 citation
arXivHTMLPDF

Abstract

In this work, we develop a design methodology to generate spectrally pure photon pairs in asymmetric heterogeneously coupled waveguides by spontaneous parametric down conversion. Mode coupling in a system of waveguides is used to directly tailor the group velocity of a supermode to achieve group velocity matching that is otherwise not allowed by material dispersion. Design examples based on thin film lithium niobate waveguides are provided, demonstrating high spectral purity and temperature tunability. This approach is a versatile strategy applicable to waveguides of different materials and structures, allowing more versatility in single-photon source designs.

DOI
10.1364/ol.430988

Related papers

Heterogeneously coupled waveguides for pure single photon generation

Xiangyan Ding, Jing Ma, Liying Tan +2 more

Single-photon sources are the cornerstone of the optical quantum information process, including quantum computing, simulation, metrology, etc. The practical application requires these sources to be high purity and indistinguishability. A readily available approach is to use heralded single-photon sources to generate photon pairs via spontaneous parametric down-conversion (SPDC). However, the purity of photon pairs generated by SPDC is usually limited by the spectral correlations because of energy conservation. Extra spectral filters and group velocity matching (GVM) can be used to generate spectral uncorrelated photon pairs on-chip. However, the material dispersion of most materials cannot meet the GVM requirements, and extra components will reduce the integration. In this work, we develop a strategy to generate pure single photon on-chip by mode coupling in heterogeneously coupled waveguides. This strategy can tailor the group velocity directly, or shape biphoton wave function through a new degree of freedom that is the non-constant overlap between interacting modes. This allows the generation of high-purity single photons totally on-chip. Design examples based on lithium niobate waveguide are provided to generate spectrally pure photon pairs. This strategy is generic that it is not limited to any material and waveguide system, providing new possibilities in the generation of quantum photons.

Tenth International Conference on Information Optics and Photonics•Dec 15, 2022•1 citation

Uncorrelated photon pair generation in asymmetric heterogeneously coupled waveguides

Xiangyan Ding, Jing Ma, Liying Tan +2 more

We develop a technique to tailor modal group velocities in asymmetric heterogeneously coupled waveguides such that uncorrelated photon pairs can be generated directly. Design examples based on lithium niobate thin film waveguides are provided.

Conference on Lasers and Electro-Optics•Jan 1, 2021•0 citations

Avoiding lateral mode leakage in thin film lithium niobate waveguides for the generation of spectrally pure photons at telecom wavelengths

Muskan Arora, Pranav Chokkara, Jasleen Lugani

Abstract Photonic integrated optical components, notably straight waveguides, serve as pivotal elements for on-chip generation and manipulation of quantum states of light. In this work, we focus on optimizing waveguides based on lithium niobate on insulator (LNOI) to generate photon pairs at telecom wavelengths using spontaneous parametric down-conversion (SPDC). Specifically, we investigate lateral leakage for all possible SPDC processes involving type 0, type I, and type II phase matching conditions in an X-cut lithium niobate waveguide and provide a recipe to avoid leakage loss for the interacting photons. Furthermore, focusing on type II phase matching, we engineer the waveguide in the single-mode regime such that it also satisfies group index matching for generating spectrally pure single photons with high purity (99.33%). We also address fabrication imperfections of the optimized design and find that the spectral purity of the generated photons is robust to fabrication errors. This work offers guidance for the suitable selection of morphological parameters to obtain lossless, single-mode LNOI waveguides for building linear optical circuits and photon pair generation at telecom wavelengths using desired phase-matching conditions.

Journal of Physics B Atomic Molecular and Optical Physics•Jun 27, 2024•3 citations

Single mode thin film lithium niobate waveguides for the generation of spectrally pure single photons at telecommunication wavelengths

Muskan Arora, Pranav Chokkara, Jasleen Lugani

In this work, we focus on optimizing waveguides based on Lithium Niobate on Insulator (LNOI) for the generation of cross-polarized spectrally pure photons at telecommunication wavelength using type II spontaneous Parametric Down-Conversion (SPDC) process. Our optimization process is based on avoiding lateral leakage losses for all the modes involved in considered SPDC process by choosing waveguide parameters appropriately. In addition, we also ensure single mode operation for all the interacting wavelengths. We further engineer the waveguide such that it satisfies group index matching for generating spectrally pure single photons with high purity (⪆95 %). Such single-mode and loss-free waveguides are poised to have broad applications in both classical and quantum optical fields.

SPIE Quantum Technologies•Apr 5, 2024•0 citations

Avoiding lateral mode leakage in thin film lithium niobate waveguides for the generation of spectrally pure photons at telecom wavelengths

Muskan Arora, Pranav Chokkara, Jasleen Lugani

Photonic integrated optical components, notably straight waveguides, serve as pivotal elements for on-chip generation and manipulation of quantum states of light. In this work, we focus on optimizing waveguides based on lithium niobate on insulator (LNOI) to generate photon pairs at telecom wavelength using spontaneous parametric down-conversion (SPDC). Specifically, we investigate lateral leakage for all possible SPDC processes involving type 0, type I and type II phase matching conditions in an X-cut lithium niobate waveguide and provide a recipe to avoid leakage loss for the interacting photons. Furthermore, focusing on type II phase matching, we engineer the waveguide in the single mode regime such that it also satisfies group index matching for generating spectrally pure single photons with high purity (99.33%). We also address fabrication imperfections of the optimized design and found that the spectral purity of the generated photons is robust to fabrication errors. This work serves as a tutorial for the appropriate selection of morphological parameters to obtain lossless, single mode LNOI waveguides for building linear optical circuits and photon pair generation at telecom wavelengths using desired phase-matching conditions.

arXiv:2402.05694•Feb 8, 2024•0 citations

Generation of broadband polarization-orthogonal photon pairs via the dispersion-engineered thin-film lithium niobate waveguide

Ji-Ning Zhang, Tong-Yu 同宇 Zhang 张, Jia-Chen Duan +2 more

Abstract Broadband photon pairs are highly desirable for quantum metrology, quantum sensing, and quantum communication. Such sources are usually designed through type-0 phase-matching spontaneous parametric down-conversion (SPDC) that makes the photon pairs hard to separate in the frequency-degenerate case and thus limits their applications. In this paper, we design a broadband frequency-degenerate telecom-band photon pair source via the type-II SPDC in a dispersion-engineered thin-film lithium niobate waveguide, where the polarization modes of photon pairs are orthogonal and thus are easily separated deterministically. With a 5-mm-long waveguide, our design can achieve a bandwidth of 5.56 THz (44.8 nm), which is 8.6 times larger than that of the bulk lithium niobate, and the central wavelength can be flexibly adjusted. Our design is a promising approach towards high-quality integrated photon sources and may have wide applications in photonic quantum technologies.

Chinese Physics B•Aug 30, 2024•3 citations
In this work, we develop a design methodology to generate spectrally pure photon pairs in asymmetric heterogeneously coupled waveguides by spontaneous parametric down conversion. Mode coupling in a system of waveguides is used to directly tailor the group velocity of a supermode to achieve group velocity matching that is otherwise not allowed by material dispersion. Design examples based on thin film lithium niobate waveguides are provided, demonstrating high spectral purity and temperature tunability. This approach is a versatile strategy applicable to waveguides of different materials and structures, allowing more versatility in single-photon source designs.
Single-photon sources are the cornerstone of the optical quantum information process, including quantum computing, simulation, metrology, etc. The practical application requires these sources to be high purity and indistinguishability. A readily available approach is to use heralded single-photon sources to generate photon pairs via spontaneous parametric down-conversion (SPDC). However, the purity of photon pairs generated by SPDC is usually limited by the spectral correlations because of energy conservation. Extra spectral filters and group velocity matching (GVM) can be used to generate spectral uncorrelated photon pairs on-chip. However, the material dispersion of most materials cannot meet the GVM requirements, and extra components will reduce the integration. In this work, we develop a strategy to generate pure single photon on-chip by mode coupling in heterogeneously coupled waveguides. This strategy can tailor the group velocity directly, or shape biphoton wave function through a new degree of freedom that is the non-constant overlap between interacting modes. This allows the generation of high-purity single photons totally on-chip. Design examples based on lithium niobate waveguide are provided to generate spectrally pure photon pairs. This strategy is generic that it is not limited to any material and waveguide system, providing new possibilities in the generation of quantum photons.
Abstract Photonic integrated optical components, notably straight waveguides, serve as pivotal elements for on-chip generation and manipulation of quantum states of light. In this work, we focus on optimizing waveguides based on lithium niobate on insulator (LNOI) to generate photon pairs at telecom wavelengths using spontaneous parametric down-conversion (SPDC). Specifically, we investigate lateral leakage for all possible SPDC processes involving type 0, type I, and type II phase matching conditions in an X-cut lithium niobate waveguide and provide a recipe to avoid leakage loss for the interacting photons. Furthermore, focusing on type II phase matching, we engineer the waveguide in the single-mode regime such that it also satisfies group index matching for generating spectrally pure single photons with high purity (99.33%). We also address fabrication imperfections of the optimized design and find that the spectral purity of the generated photons is robust to fabrication errors. This work offers guidance for the suitable selection of morphological parameters to obtain lossless, single-mode LNOI waveguides for building linear optical circuits and photon pair generation at telecom wavelengths using desired phase-matching conditions.
In this work, we focus on optimizing waveguides based on Lithium Niobate on Insulator (LNOI) for the generation of cross-polarized spectrally pure photons at telecommunication wavelength using type II spontaneous Parametric Down-Conversion (SPDC) process. Our optimization process is based on avoiding lateral leakage losses for all the modes involved in considered SPDC process by choosing waveguide parameters appropriately. In addition, we also ensure single mode operation for all the interacting wavelengths. We further engineer the waveguide such that it satisfies group index matching for generating spectrally pure single photons with high purity (⪆95 %). Such single-mode and loss-free waveguides are poised to have broad applications in both classical and quantum optical fields.
Photonic integrated optical components, notably straight waveguides, serve as pivotal elements for on-chip generation and manipulation of quantum states of light. In this work, we focus on optimizing waveguides based on lithium niobate on insulator (LNOI) to generate photon pairs at telecom wavelength using spontaneous parametric down-conversion (SPDC). Specifically, we investigate lateral leakage for all possible SPDC processes involving type 0, type I and type II phase matching conditions in an X-cut lithium niobate waveguide and provide a recipe to avoid leakage loss for the interacting photons. Furthermore, focusing on type II phase matching, we engineer the waveguide in the single mode regime such that it also satisfies group index matching for generating spectrally pure single photons with high purity (99.33%). We also address fabrication imperfections of the optimized design and found that the spectral purity of the generated photons is robust to fabrication errors. This work serves as a tutorial for the appropriate selection of morphological parameters to obtain lossless, single mode LNOI waveguides for building linear optical circuits and photon pair generation at telecom wavelengths using desired phase-matching conditions.
Abstract Broadband photon pairs are highly desirable for quantum metrology, quantum sensing, and quantum communication. Such sources are usually designed through type-0 phase-matching spontaneous parametric down-conversion (SPDC) that makes the photon pairs hard to separate in the frequency-degenerate case and thus limits their applications. In this paper, we design a broadband frequency-degenerate telecom-band photon pair source via the type-II SPDC in a dispersion-engineered thin-film lithium niobate waveguide, where the polarization modes of photon pairs are orthogonal and thus are easily separated deterministically. With a 5-mm-long waveguide, our design can achieve a bandwidth of 5.56 THz (44.8 nm), which is 8.6 times larger than that of the bulk lithium niobate, and the central wavelength can be flexibly adjusted. Our design is a promising approach towards high-quality integrated photon sources and may have wide applications in photonic quantum technologies.