Soliton microcombs in X-cut LiNbO3 microresonators

• 出版年: eLight
• 主要な著者: Binbin Nie, Xiaomin Lv, Chen Yang, Rui Ma, Kaixuan Zhu, Ze Wang, Yanwu Liu, Zhenyu Xie, Xing Jin, Guanyu Zhang, Du Qian, Zhenyu Chen, Qiang Luo, Shuting Kang, Guowei Lv, Qihuang Gong, Fang Bo, Qi-Fan Yang
• フォーマット: 論文
• 言語: 英語
• 出版事項: SpringerOpen 2025-07-01
• 主題: Thin film lithium niobate; Optical frequency comb; Optical microresonator; Nonlinear photonics
• オンライン･アクセス: https://doi.org/10.1186/s43593-025-00093-x
• ISSN: 2097-1710; 2662-8643

Abstract Chip-scale integration of optical frequency combs, particularly soliton microcombs, enables miniaturized instrumentation for timekeeping, ranging, and spectroscopy. Although soliton microcombs have been demonstrated on various material platforms, realizing complete comb functionality on photonic chips requires the co-integration of high-speed modulators and efficient frequency doublers, features that are available in a monolithic form on X-cut thin-film lithium niobate (TFLN). However, the pronounced Raman nonlinearity associated with extraordinary light in this platform has so far precluded soliton microcomb generation. Here, we report the generation of transverse-electric-polarized soliton microcombs with a 25 GHz repetition rate in high-Q microresonators on X-cut TFLN chips. By precisely orienting the racetrack microresonator relative to the optical axis, we mitigate Raman nonlinearity and enable soliton formation under continuous-wave laser pumping. Moreover, the soliton microcomb spectra are extended to 350 nm with pulsed laser pumping. This work expands the capabilities of TFLN photonics and paves the way for the monolithic integration of fast-tunable, self-referenced microcombs.