Nonlinear phase-matched van der Waals crystals integrated on optical fibres

Kaifeng Lin; Guangjie Yao; Jiahui Shao; Yilong You; Jiajie Qi; Daopeng Yuan; Yijun Wang; Muhong Wu; Lingjun Kong; Xiangdong Zhang; Enge Wang; Zhipei Sun; Hao Hong; Kaihui Liu

doi:10.1038/s41563-025-02461-x

Nonlinear phase-matched van der Waals crystals integrated on optical fibres

Kaifeng Lin
, Guangjie Yao
, Jiahui Shao
, Yilong You
, Jiajie Qi
, Daopeng Yuan
, Yijun Wang
, Muhong Wu
, Lingjun Kong
, Xiangdong Zhang
, Enge Wang
, Zhipei Sun^*
, Hao Hong^*
, Kaihui Liu^*

^*Corresponding author for this work

Beijing Institute of Technology
Peking University
Shandong University
Beihang University
Songshan Lake Materials Laboratory

Research output: Contribution to journal › Article › Scientific › peer-review

4 Citations (Scopus)

Abstract

High optical nonlinearity can enable classical and quantum functionalities in all-fibre laser systems. However, despite long-standing efforts to exploit second-order optical nonlinearity in conventional all-fibre systems, nonlinear optical conversion efficiencies remain modest. Here we demonstrate all-fibre integration of twist-phase-matched rhombohedral boron nitride (rBN) flakes on the end facet of optical fibres for second-harmonic generation (SHG) and spontaneous parametric downconversion (SPDC). We provide local and global optimization of the interflake twist angles for phase-matching design, achieving an SHG conversion efficiency of similar to 4.1% and an SPDC coincidence rate of similar to 90 in van der Waals crystals integrated on optical fibre devices. Finally, we design an all-fibre frequency-doubling ultrafast laser by integrating a multifunctional nonlinear crystal of a graphene/rBN heterostructure to simultaneously generate mode-locked pulses and intracavity SHG emission. This work establishes a route for developing high-efficiency, second-order nonlinear functionalities, such as optical parametric oscillators, optical modulators and entangled photon sources, in all-fibre lasers.

Original language	English
Pages (from-to)	581-587
Number of pages	7
Journal	Nature Materials
Volume	25
Issue number	4
Early online date	2026
DOIs	https://doi.org/10.1038/s41563-025-02461-x
Publication status	Published - Apr 2026
MoE publication type	A1 Journal article-refereed

Funding

This work was supported by the National Natural Science Foundation of China (12427806 (K. Liu), 52025023 (K. Liu), T2188101 (K. Liu), 12422406 (H.H.), 51991342 (K. Liu), 12374167 (H.H.) and 52172035 (M.W.)), National Key R&D Program of China (2022YFA1403504 (K. Liu), 2021YFA1400201 (H.H.) and 2021YFA1400502 (M.W.)), Guangdong Major Project of Basic and Applied Basic Research (2021B0301030002 (K. Liu)), the Strategic Priority Research Program of Chinese Academy of Sciences (XDB33000000 (K. Liu)), the Research Council of Finland Flagship Programme (320167, PREIN (Z.S.)), ERC (834742 (Z.S.)) and the New Cornerstone Science Foundation through the XPLORER PRIZE (K. Liu).

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10.1038/s41563-025-02461-x

Cite this

@article{19d09079712d4dda83c836779610a05c,

title = "Nonlinear phase-matched van der Waals crystals integrated on optical fibres",

abstract = "High optical nonlinearity can enable classical and quantum functionalities in all-fibre laser systems. However, despite long-standing efforts to exploit second-order optical nonlinearity in conventional all-fibre systems, nonlinear optical conversion efficiencies remain modest. Here we demonstrate all-fibre integration of twist-phase-matched rhombohedral boron nitride (rBN) flakes on the end facet of optical fibres for second-harmonic generation (SHG) and spontaneous parametric downconversion (SPDC). We provide local and global optimization of the interflake twist angles for phase-matching design, achieving an SHG conversion efficiency of similar to 4.1\% and an SPDC coincidence rate of similar to 90 in van der Waals crystals integrated on optical fibre devices. Finally, we design an all-fibre frequency-doubling ultrafast laser by integrating a multifunctional nonlinear crystal of a graphene/rBN heterostructure to simultaneously generate mode-locked pulses and intracavity SHG emission. This work establishes a route for developing high-efficiency, second-order nonlinear functionalities, such as optical parametric oscillators, optical modulators and entangled photon sources, in all-fibre lasers.",

author = "Kaifeng Lin and Guangjie Yao and Jiahui Shao and Yilong You and Jiajie Qi and Daopeng Yuan and Yijun Wang and Muhong Wu and Lingjun Kong and Xiangdong Zhang and Enge Wang and Zhipei Sun and Hao Hong and Kaihui Liu",

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year = "2026",

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doi = "10.1038/s41563-025-02461-x",

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T1 - Nonlinear phase-matched van der Waals crystals integrated on optical fibres

AU - Lin, Kaifeng

AU - Yao, Guangjie

AU - Shao, Jiahui

AU - You, Yilong

AU - Qi, Jiajie

AU - Yuan, Daopeng

AU - Wang, Yijun

AU - Wu, Muhong

AU - Kong, Lingjun

AU - Zhang, Xiangdong

AU - Wang, Enge

AU - Sun, Zhipei

AU - Hong, Hao

AU - Liu, Kaihui

N1 - Publisher Copyright: © The Author(s), under exclusive licence to Springer Nature Limited 2026. | openaire: EC/H2020/834742/EU//ATOP

PY - 2026/4

Y1 - 2026/4

N2 - High optical nonlinearity can enable classical and quantum functionalities in all-fibre laser systems. However, despite long-standing efforts to exploit second-order optical nonlinearity in conventional all-fibre systems, nonlinear optical conversion efficiencies remain modest. Here we demonstrate all-fibre integration of twist-phase-matched rhombohedral boron nitride (rBN) flakes on the end facet of optical fibres for second-harmonic generation (SHG) and spontaneous parametric downconversion (SPDC). We provide local and global optimization of the interflake twist angles for phase-matching design, achieving an SHG conversion efficiency of similar to 4.1% and an SPDC coincidence rate of similar to 90 in van der Waals crystals integrated on optical fibre devices. Finally, we design an all-fibre frequency-doubling ultrafast laser by integrating a multifunctional nonlinear crystal of a graphene/rBN heterostructure to simultaneously generate mode-locked pulses and intracavity SHG emission. This work establishes a route for developing high-efficiency, second-order nonlinear functionalities, such as optical parametric oscillators, optical modulators and entangled photon sources, in all-fibre lasers.

AB - High optical nonlinearity can enable classical and quantum functionalities in all-fibre laser systems. However, despite long-standing efforts to exploit second-order optical nonlinearity in conventional all-fibre systems, nonlinear optical conversion efficiencies remain modest. Here we demonstrate all-fibre integration of twist-phase-matched rhombohedral boron nitride (rBN) flakes on the end facet of optical fibres for second-harmonic generation (SHG) and spontaneous parametric downconversion (SPDC). We provide local and global optimization of the interflake twist angles for phase-matching design, achieving an SHG conversion efficiency of similar to 4.1% and an SPDC coincidence rate of similar to 90 in van der Waals crystals integrated on optical fibre devices. Finally, we design an all-fibre frequency-doubling ultrafast laser by integrating a multifunctional nonlinear crystal of a graphene/rBN heterostructure to simultaneously generate mode-locked pulses and intracavity SHG emission. This work establishes a route for developing high-efficiency, second-order nonlinear functionalities, such as optical parametric oscillators, optical modulators and entangled photon sources, in all-fibre lasers.

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DO - 10.1038/s41563-025-02461-x

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VL - 25

SP - 581

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JO - Nature Materials

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Nonlinear phase-matched van der Waals crystals integrated on optical fibres

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Nonlinear phase-matched van der Waals crystals integrated on optical fibres

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