The absence of the single-photon nonlinearity has been a major roadblock in developing quantum photonic circuits at optical frequencies. In this paper, we demonstrate a periodically-poled thin film lithium niobate microring resonator (PPLNMR) that reaches 5,000,000%/W second harmonic conversion efficiency---almost 20-fold enhancement over the state-of-the-art---by accessing its largest $χ^{(2)}$ tensor component $d_{33}$ via quasi-phase matching. The corresponding single photon coupling rate $g/2π$ is estimated to be 1.2 MHz, which is an important milestone as it approaches the dissipation rate $κ/2π$ of best available lithium niobate microresonators developed in the community. Using a figure of merit defined as $g/κ$, our devices reach a single photon nonlinearity approaching 1%. We show that, by further scaling of the device, it is possible to improve the single photon nonlinearity to a regime where photon-blockade effect can be manifested.
Thin-film lithium niobate is an attractive integrated photonics platform due to its low optical loss and favorable optical nonlinear and electro-optic properties. However, in applications such as second harmonic generation, frequency comb generation, and microwave-to-optics conversion, the device performance is strongly impeded by the photorefractive effect inherent in thin-films. In this paper, we show that the dielectric cladding on lithium niobate microring resonator has a significant influence on the photorefractive effect. By removing the dielectric cladding layer, the photorefractive eff…
We demonstrate ultra-high Q factor microring resonators close to the intrinsic material absorption limit on lithium niobate on insulator. The microrings are fabricated on pristine lithium niobate (LN) thin film wafer thinned from LN bulk via chemo-mechanical etching without ion slicing and ion etching. A record-high Q factor up to times ten to the power of 8th at the wavelength of 1550 nm is achieved because of the ultra-smooth interface of the microrings and the absence of ion induced lattice damage, indicating an ultra-low waveguide propagation loss of about 0.28 dB per meter. The ultra-high…
We demonstrate monolithic integration of an electro-optically (EO) tunable microring laser on lithium niobate on insulator (LNOI) platform. The device is fabricated by photolithography assisted chemo-mechanical etching (PLACE), and the pump laser is evanescently coupled into the erbium (Er3+) doped LN microring laser using an undoped LN waveguide mounted above the microring. The quality factor of the LN microring resonator is measured as high as 1.54x10^5 at the wavelength of 1542 nm. Lasing action can be observed at a pump power threshold below 3.5 mW using a 980 nm continuous-wave pump laser…
Systematic Analysis of Ferroelectric Domain Dynamics in Periodically Poled Lithium Niobate Waveguides Using Two-Photon Microscopy and Digital Imaging Processing
Phase Sensitive Innovations Inc（Phase Sensitive Innovations 公司）；University of Delaware（特拉华大学）
Ultra-efficient and highly-tunable second-harmonic generation in Z-cut periodically poled lithium niobate nanowaveguides
薄膜绝缘体上的锂氧化物（LNOI）已经成为用于线性、非线性和电光的优异集成光子学平台。在这里，我们结合准相位匹配，色散工程，和紧模式限制，实现高效率和宽波长可调谐性的非线性参量过程。在毫米长的Z切LNOI波导上，我们通过0型准相位匹配展示了超高效（$1900\pm500 \% $ W $^{-1}$ cm $^{-2}$）和高度可调谐（-1.71 nm/K）的从1530 nm到1583 nm的二次谐波产生。我们的技术适用于光学谐波产生，量子光源，频率转换，和许多其他光子信息处理在可见光到中红外光谱带。
18-dB on-chip vacuum squeezing in an adaptively poled lithium niobate waveguide
University of California, Berkeley（加州大学伯克利分校）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California（南加州大学明希电气与计算机工程系）；Research Laboratory of Electronics, MIT（麻省理工学院电子研究实验室）；Department of Electrical and Computer Engineering, University of Hawaii at Mānoa（夏威夷大学马诺阿分校电气与计算机工程系）
Lithium niobate on insulator (LNOI) is extensively researched for potential applications in telecommunication, sensing and quantum technology. Low-loss waveguides in LNOI have been demonstrated in recent years, with further works investigating their nonlinear optical properties via electric field poling. The fabrication imperfections and minimum feature size of inverted ferroelectric domains currently limit the efficiency and application of nonlinear processes in LNOI. This work looks into focused ion beam poling and demonstrates its potential to overcome the limitations of electric field poli…
Simultaneous generation of Raman-assisted Soliton Microcombs and Tunable Multi-chromatic Raman Microlasers in Single Monolithic Thin-film Lithium Niobate Microrings
Segment-chirped periodically poled lithium niobate waveguides for broadband supercontinuum generation
National University of Singapore（新加坡国立大学）；Sichuan University（四川大学）；A ∗ STAR Quantum Innovation Centre (Q.InC), Agency for Science, Technology and Research (A ∗ STAR)（A*STAR量子创新中心（Q.InC），科学技术研究局（A*STAR））；Nanyang Technological University（南洋理工大学）
Lithium niobate on insulator (LNOI), regarded as an important candidate platform for optical integration due to its excellent nonlinear, electro-optic and other physical properties, has become a research hotspot. Light source, as an essential component for integrated optical system, is urgently needed. In this paper, we reported the realization of 1550-nm band on-chip LNOI microlasers based on erbium-doped LNOI ring cavities with loaded quality factors higher than one million, which were fabricated by using electron beam lithography and inductively coupled plasma reactive ion etching processes…
Quantum squeezing in an all-resonant periodically poled lithium niobate microresonator
University of California, Berkeley（加州大学伯克利分校）；Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California（南加州大学明海电气与计算机工程学院）；Materials Sciences Division, Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室材料科学部）
High-Q Lithium Niobate Microring Resonator with Electro-Optically Reconfigurable Coupling Strength
Shanghai Research Center for Quantum Sciences（上海量子科学研究中心）；State Key Laboratory of Precision Spectroscopy, East China Normal University（精密光谱学国家重点实验室，华东师范大学）；The Extreme Optoelectromechanics Laboratory (XXL), School of Physics, East China Normal University（极端光机电实验室（XXL），物理学院，华东师范大学）；WLSA Shanghai Academy（WLSA上海学院）；Hefei National Laboratory（合肥国家实验室）；Collaborative Innovation Center of Extreme Optics, Shanxi University（极端光学协同创新中心，山西大学）
Isotropic fabrication of centimeter-scale, low propagation-loss periodically poled lithium niobate nanophotonic waveguides for efficient second harmonic generation
Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences（中国科学院上海光学精密机械研究所）；East China Normal University（华东师范大学）；ShanghaiTech University（上海科技大学）；University of Chinese Academy of Sciences（中国科学院大学）；Shanghai Research Center for Quantum Sciences（上海量子科学研究中心）；Hefei National Laboratory（合肥国家实验室）；Shanxi University（山西大学）；Shandong Normal University（山东师范大学）
We overcome the difficulty in realizing a monolithic waveguide-coupled microring laser integrated on erbium-doped thin film lithium niobate (Er: TFLN) using photolithography assisted chemo-mechanical etching (PLACE) technique. We demonstrate an integrated single-frequency microring laser operating around 1531 nm wavelength. The PLACE technique, enabling integrated Er: TFLN photonics with low propagation loss, can thus be used to realize low cost mass production of monolithic on-chip microlasers with applications ranging from optical communication and photonic integrated circuit (PIC) to precis…
Offset Dual Microcombs in a Single Microresonator: Kerr-Raman Interleaved Combs
East China Normal University（华东师范大学）；Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences（中国科学院上海光学精密机械研究所）；Nanjing University（南京大学）；Shanghai Research Center for Quantum Sciences（上海量子科学研究与创新中心）；Hefei National Laboratory（合肥国家实验室）；Collaborative Innovation Center of Extreme Optics, Shanxi University（山西大学极端光学协同创新中心）；Collaborative Innovation Center of Light Manipulations and Applications, Shandong Normal University（山东师范大学光调控与应用协同创新中心）
