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铌酸锂集成光子芯片端面耦合器件(特邀)

激光与光电子学进展 2024年第11期61卷 164-173页

作者：贾笛郝振中薄方张国权许京军弱光非线性光子学教育部重点实验室南开大学泰达应用物理研究院物理科学学院天津300457

薄膜铌酸锂(TFLN)具有优异的电光和光学非线性特性,是开展电光调制器、非线性光学频率转换器等相关研究的重要平台。然而,由于TFLN片上光波导与光纤模场尺寸存在显著差异,严重限制了二者之间的高效耦合。因此,高效率端面耦合器成为了突... 详细信息

薄膜铌酸锂(TFLN)具有优异的电光和光学非线性特性,是开展电光调制器、非线性光学频率转换器等相关研究的重要平台。然而,由于TFLN片上光波导与光纤模场尺寸存在显著差异,严重限制了二者之间的高效耦合。因此,高效率端面耦合器成为了突破TFLN集成光学芯片应用限制瓶颈的重要手段。将对TFLN端面耦合器的研究进展进行系统综述,首先介绍常见的几种参与端面耦合的光纤特性;然后,介绍端面耦合器中铌酸锂端面耦合波导的典型结构,如单层或多层倒锥形波导、楔形波导等,并对相关的包层材料的选择及制备方法进行讨论;最后,对端面耦合器研究现状、存在的问题等做出总结,并展望未来可能的发展方向。

关键词：薄膜铌酸锂端面耦合器倒锥形波导楔形波导

基于FPGA的视频图像去雾算法的优化与实现

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电子技术应用 2024年第5期50卷 90-96页

作者：郝振中余耀孙静安徽新华学院电子工程学院/智能制造学院安徽合肥230088 无锡学院电子与信息工程学院江苏无锡214063

在恶劣天气条件下采集的图像存在对比度差、清晰度下降等问题。图像质量的恶化制约着计算机视觉的准确性和自动化任务的效率。给出了一种基于限制对比度自适应直方图均衡(Contrast Limited Adaptive Histogram Equalization,CLAHE)与改... 详细信息

在恶劣天气条件下采集的图像存在对比度差、清晰度下降等问题。图像质量的恶化制约着计算机视觉的准确性和自动化任务的效率。给出了一种基于限制对比度自适应直方图均衡(Contrast Limited Adaptive Histogram Equalization,CLAHE)与改进多尺度Retinex(Multi-Scale retinex,MSR)的图像去雾算法。该算法将输入的含雾降质图像先经过CLAHE算法处理,再用MSR算法处理,对图像MSR算法处理时,引入Gamma校正因子估计入射光,并对算法中的环绕函数进行优化。结果表明,所提出算法处理后的图像相比原图,图像的信息熵、平均梯度和标准差等方面均有提升;并设计硬件电路,成功在FPGA上演示了视频实时去雾,提高了视频图像去雾的实时性。对板级资源与功能消耗进行了数字化的分析,证明所设计硬件系统属于低功耗范畴。

关键词：图像质量 CLAHE 多尺度Retinex FPGA 视频去雾

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用于图像边缘检测的SOC FPGA系统

计算机与数字工程 2024年第8期52卷 2317-2322页

作者：郝振中余耀赵东南京信息工程大学南京210044 无锡学院无锡214105

图像处理领域中,往往存在着软件处理实时性较差、FPGA硬件功耗大、片上资源使用较多的问题。为此,论文设计了一种资源消耗少、处理速度快的图像边缘检测系统。在FPGA上实现图像采集、图像灰度化、二值化、形态学滤波、优化的Canny边缘... 详细信息

图像处理领域中,往往存在着软件处理实时性较差、FPGA硬件功耗大、片上资源使用较多的问题。为此,论文设计了一种资源消耗少、处理速度快的图像边缘检测系统。在FPGA上实现图像采集、图像灰度化、二值化、形态学滤波、优化的Canny边缘检测算法等功能,由硬核处理器实现外设及其IP核的映射,并配置摄像头、DDR3等设备的驱动程序。通过AXI总线协议实现HPS到FPGA的桥接,完成整个SOC FPGA系统的搭建。图像检测结果表明,该图像处理系统资源消耗低、实时性较高,继承了SOC与FPGA的双重优势,为图像处理方法与应用提供了新的发展方向。

关键词：片上系统边缘检测硬核处理系统 FPGA

Second-harmonic generation using d(33)in periodically poled lithium niobate microdisk resonators

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Photonics Research 2020年第3期8卷 311-317页

作者： zhenzhong hao LI ZHANG WENBO MAO ANG GAO XIAOMEI GAO FENG GAO FANG BO GUOQUAN ZHANG JINGJUN XU MOE Key Laboratory of Weak-Light Nonlinear Photonics TEDA Institute of Applied Physics and School of PhysicsNankai UniversityTianjin 300457China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China

A fabrication process allowing for the production of periodically poled lithium niobate(PPLN)photonic devices with any domain pattern and unit size down to 200 nm is developed by combining semiconductor fabrication techniques and piezo-force-microscopy tips *** on this fabrication process,PPLN microdisk resonators with quality factors of 8×10~4 were fabricated from a Z-cut lithium niobate ***-harmonic generation(SHG)utilizing d(33)in the whole cavity was demonstrated in a PPLN microdisk with a 2μm-spatialperiod radial domain *** SHG conversion efficiency was measured to be 1.44×10^(-5)m W^(-1).This work paves the way to fabricate complex PPLN photonic devices and to obtain efficient nonlinear optical effects that have wide applications in both classical and quantum optics.

关键词： lithium harmonic niobate

Periodically poled lithium niobate whispering gallery mode microcavities on a chip

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Science China(Physics,Mechanics & Astronomy) 2018年第11期61卷 36-40页

作者： zhenzhong hao Li Zhang Ang Gao WenBo Mao XiaoDan Lyu XiaoMei Gao Fang Bo Feng Gao GuoQuan Zhang JingJun Xu MOE Key Laboratory of Weak Light Nonlinear Photonics TEDA Institute of Applied Physics and School of Physics Nankai University Tianjin 300457 China The Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan 030006 China

In this study, we investigate the fabrication of periodically poled lithium niobate(PPLN) microdisk cavities on a chip. These resonators are fabricated from a PPLN film with a 16 μm poling period on insulator using conventional microfabrication *** quality factor of the PPLN microdisk resonators with a 40-μm radius and a 700-nm thickness is 6.7×10~5. Second harmonic generation(SHG) with an efficiency of 2.2×10^(-6) mW(-1) is demonstrated in the fabricated PPLN microdisks. The nonlinear conversion efficiency could be considerably enhanced by optimizing the period and pattern of the poled structure and by improving the cavity quality factors.

关键词： whispering gallery mode periodically poled lithium niobate microcavities second harmonic generation

Integrated lithium niobate single-mode lasers by the Vernier effect

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Science China(Physics,Mechanics & Astronomy) 2021年第9期64卷 82-86页

作者： Ru Zhang Chen Yang zhenzhong hao Di Jia Qiang Luo DaHuai Zheng HongDe Liu XuanYi Yu Feng Gao Fang Bo YongFa Kong GuoQuan Zhang JingJun Xu MOE Key Laboratory of Weak-Light Nonlinear Photonics TEDA Institute of Applied Physics and School of PhysicsNankai UniversityTianjin 300457China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China Collaborative Innovation Center of Light Manipulations and Applications Shandong Normal UniversityJinan 250358China

Microcavity lasers based on erbium-doped lithium niobate on insulator(LNOI),which are key devices for LNOI integrated photonics,have attracted significant attention *** this study,we report the realization of a C-band single-mode laser using the Vernier effect in two coupled erbium-doped LNOI microrings with different radii under the pump of a 980-nm continuous *** laser,operating stably over a large range of pumping power,has a pump threshold of about 200μW and a side-mode suppression ratio exceeding 26 *** high-performance LNOI single-mode laser will promote the development of lithium niobate integrated photonics.

关键词： lithium niobate LNOI microcavities single-mode laser

Sum-frequency generation in on-chip lithium niobate microdisk resonators

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Photonics Research 2017年第6期5卷 142-147页

作者： zhenzhong hao JIE WANG SHUQIONG MA WENBO MAO FANG BO FENG GAO GUOQUAN ZHANG JINGJUN XU The MOE Key Laboratory of Weak Light Nonlinear Photonics TEDA Institute of Applied Physics and School of PhysicsNankai University The Collaborative Innovation Center of Extreme Optics Shanxi University

We report the first observation, to the best of our knowledge, of sum-frequency generation in on-chip lithium niobate microdisk resonators. The sum-frequency signal in the 780 nm band, distinct in wavelength from secondharmonic signals, was obtained in lithium niobate microresonators under the pump of two individual 1550 nm band lasers. The sum-frequency conversion efficiency was measured to be 1.4 × 10^(-7) mW^(-1). The dependence of the intensities of the nonlinear signals on the total pump power and the wavelength of one pump laser was investigated while fixing the wavelength of the other. This work paves the way for applications of on-chip lithium niobate microdisk resonators ranging from infrared single-photon detection to infrared spectroscopy.

关键词： SFG Sum-frequency generation in on-chip lithium niobate microdisk resonators SHG

Directional emission in X-cut lithium niobate microresonators without chaos dynamics

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Photonics Research 2022年第2期10卷 401-406页

作者： Ang Gao Chen Yang Likun Chen Ru Zhang Qiang Luo Wei Wang Qitao Cao zhenzhong hao Fang Bo Guoouan Zhang Jingjun Xu MOE Key Laboratory of Weak-Light Nonlinear Photonics TEDA Institute of Applied Physics and School of PhysicsNankai UniversityTianjin 300457China State Key Laboratory for Artificial Microstructure and Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China

We systematically investigate the field distribution of the transverse electric modes in X-cut lithium niobate disks as an example of circular microcavities with anisotropic refractive index. A conserved quantity is discovered, which indicates the absence of chaos that generally exists in deformed microcavities and leads to a nontrivial directional emission. The emission directionality was theoretically investigated and experimentally verified by exciting highorder modes of an X-cut lithium niobate microresonator assisted with second harmonics. The field distribution analysis can enrich the knowledge in designing photonic devices that need precise control of field distribution,such as phase matching in nonlinear processes. Furthermore, the discovered emission phenomenon is momentous in enhancing and controlling communications between on-chip photonic devices.

关键词： lithium chaos directional

Sum-frequency generation of a laser and its background in an on-chip lithium-niobate microdisk

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Chinese Optics Letters 2022年第11期20卷 49-52页

作者： zhenzhong hao Li Zhang Jie Wang Fang Bo Feng Gao Guoquan Zhang Jingjun Xu MOE Key Laboratory of Weak-Light Nonlinear Photonics TEDA Institute of Applied Physics and School of PhysicsNankai UniversityTianjin 300457China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China

Lithium-niobate microcavities have not only the ability to resonantly enhance light–matter interaction but also excellent nonlinear optical properties,thereby providing an important platform for nonlinear optical *** this paper,we report the observation of multi-peak spectra in the near infrared range in lithium-niobate microcavities on a chip under the pump of a 1550 nm continuous *** a multi-peak spectrum was attributed to the sum-frequency of the pump laser and its *** conversion efficiencies of the sum-frequency processes are of the order of61.5%*** influences of the phenomenon on nonlinear processes were further discussed.

关键词： lithium niobate microcavities nonlinear optics