Author Affiliations
Abstract
1 State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
2 Hefei National Laboratory, Hefei 230088, China
Silicon nitride () is an appealing waveguide material choice for large-scale, high-performance photonic integrated circuits (PICs) due to its low optical loss. However, PICs require high electric power to realize optical reconfiguration via the weak thermo-optic effect, which limits their scalability in terms of device density and chip power dissipation. We report a 6-mode programmable interferometer PIC operating at the wavelength of 1550 nm on a CMOS-compatible low-temperature inductance coupled plasma chemical vapor deposition (ICP-CVD) silicon nitride platform. By employing suspended thermo-optic phase shifters, the PIC achieves improvement in compactness and enhancement in power efficiency compared to conventional devices. Reconfigurable 6-dimensional linear transformations are demonstrated including cyclic transformations and arbitrary unitary matrices. This work demonstrates the feasibility of fabricating power-efficient large-scale reconfigurable PICs on the low-temperature ICP-CVD silicon nitride platform.
Photonics Research
2024, 12(3): A11
渤海大学化学与材料工程学院，辽宁省全谱太阳能电池转光材料专业技术创新中心，锦州 121013
本文在水热条件下成功合成了一例Keggin型多酸基超分子化合物1,其分子式为H3［(3-PA)4(PW12O40)］(3-PA=3-(3-吡啶)丙烯酸)，并通过单晶X射线衍射、元素分析(EA)、红外(IR)光谱、X射线粉末衍射(PXRD)、热重(TG)和固体紫外-可见(UV-Vis)漫反射对化合物1的结构进行了表征。化合物1属于三斜晶系，P-1空间群，a=1.200 33(3) nm，b=1.216 42(3) nm，c=1.424 66(4) nm，α=75.030(1)°，β=73.452(1)°，γ=69.372(1)°，V=1.837 00(8) nm3，Z=1，Mr=3 476.78，F(000)=1 538，μ=18.815 mm-1，Dc=3.143 mg·m-3，S=1.062，R1=0.046 2,wR2=0.138 7。化合物1的结构单元包含一个［PW12O40］3-多阴离子和四个3-PA配体，并通过［PW12O40］3-多阴离子和3-PA配体之间的氢键连接形成二维超分子层。化合物1在光催化还原Cr(Ⅵ)反应中展现出良好的光催化活性，并具有较好的结构稳定性和可循环利用性。
多金属氧酸盐 水热合成 超分子化合物 光催化 Cr(VI)还原 polyoxometalate hydrothermal synthesis supramolecular complex photocatalysis Cr(VI) reduction
Author Affiliations
Abstract
National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin 150080, China
Using a plane–plane resonator composed of silicon carbide mirrors, we achieve for the first time multi-pass amplification of a 46.9 nm laser pumped by capillary discharge. In terms of the temporal characteristics, for an initial argon pressure of 17 Pa, triple-pass amplification of the laser is obtained at a delay time between the pre-pulse and the main pulse currents of 40 µs, and quadruple-pass amplification is obtained at a delay time of 50 µs. The experimental results show that the gain duration of the plasma column is more than 6 ns. In terms of spatial characteristics, the spot of the output laser has a reduced full width at half maximum divergence compared with that from a laser without a resonator.
Matter and Radiation at Extremes
2023, 8(4): 044402
Author Affiliations
Abstract
1 School of Science, Harbin University of Science and Technology, Harbin 150080, P. R. China
2 School of Measurement and Communication Engineering, Harbin University of Science and Technology, Harbin 150080, P. R. China
In this paper, Lead-free based on 0.97()()O3–0.03TiO3 with additives La2O3 (1, 2, 3, 4 wt.%) was prepared by the solid reaction method, and the effect of La dopant on the structural and electrical properties is investigated. The result indicates La dopant considerably decreases the optical band gap compared to the undoped composition. On the other hand, La doping leads to the higher dielectric property in a wider temperature, providing possibilities and directions for the subsequent development of ferroelectric photovoltaic materials with electrical properties and low optical band gap in a dramatical manner.
Piezoelectric ceramics KNNLT-BNT dielectric properties band gap Journal of Advanced Dielectrics
2023, 13(2): 2350010
Author Affiliations
Abstract
1 School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, China
2 Guangdong Provincial Key Laboratory of Information Photonics Technology, Guangdong University of Technology, Guangzhou 510006, China
3 School of Information Engineering, Guangdong University of Technology, Guangzhou 510006, China
In this paper, a Bragg reflector is proposed by placing periodic metallic gratings in the center of a metal-insulator-metal (MIM) waveguide. According to the effective refractive index modulation caused by different waveguide widths in a period, a reflection channel with a large bandwidth is firstly achieved. Besides, the Mach-Zehnder interference (MZI) effect arises by shifting the gratings away from the waveguide center. Owing to different optical paths with unequal indices on both sides of the grating, a narrow MZI band gap will be obtained. It is interesting to find out that the Bragg reflector and Mach-Zehnder interferometer are immune to each other, and their wavelengths can be manipulated by the period and the grating length, respectively. Additionally, we can obtain three MZI channels and one Bragg reflection channel by integrating three different gratings into a large period. The performances are investigated by finite-difference time-domain (FDTD) simulations. In the index range of 1.33 – 1.36, the maximum sensitivity for the structure is as high as 1 500 nm/RIU, and it is believed that this proposed structure can find widely applications in the chip-scale optical communication and sensing areas.
Bragg reflector metal-insulator-metal Mach-Zehnder interference effective refractive index modulation Photonic Sensors
2022, 12(3): 220303
1 哈尔滨工业大学可调谐激光技术国家级重点实验室, 黑龙江 哈尔滨 150080
2 哈尔滨工业大学空间光学工程研究中心, 黑龙江 哈尔滨 150080
探究了在毛细管内充入气压比为8∶1的Ar-He混合气体条件下,初始气压对46.9 nm激光输出特性的影响。通过测量Ar-He混合气体产生46.9 nm激光的气压范围和每个气压下对应的激光强度与光斑形态信息,总结出激光输出特性与初始气压的关系。然后,从等离子体柱的角度分析了混合气体初始气压对激光光斑的影响,得到了混合气体初始气压导致46.9 nm激光输出特性发生变化的原因。以上对激光特性的研究对于提高激光幅值和改变光斑形状有益。
光学学报
2022, 42(11): 1134022
Author Affiliations
Abstract
1 State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
2 e-mail: zhangyf33@mail.sysu.edu.cn
3 e-mail: yusy@mail.sysu.edu.cn
The monolithic integration of soliton microcomb devices with active photonic components and high-frequency electronics is highly desirable for practical applications. Among many materials, silicon nitride () waveguide layers prepared by low-pressure chemical vapor deposition (LPCVD) have been the main platform for on-chip optical frequency comb generation. However, the high temperatures involved in LPCVD render it incompatible as a back-end process with complementary metal oxide semiconductor (CMOS) or active III-V compound semiconductor fabrication flows. We report the generation of coherent soliton frequency combs in micro-ring resonators fabricated in deuterated silicon nitride () waveguides with a loss of 0.09 dB/cm. Deposited at 270°C by an inductance-coupled plasma chemical vapor deposition (ICP-CVD) process, the material preparation and fabrication flow are fully CMOS-compatible. These results enable the integration of silicon-nitride-based optical combs and photonic integrated circuits (PICs) on prefabricated CMOS and/or III-V substrates, therefore marking a major step forward in photonic technologies.
Photonics Research
2022, 10(5): 05001290
1 江苏理工学院机械工程学院, 江苏 常州 213000
2 河海大学物联网学院, 江苏 常州 213000
针对存在阵风干扰及未建模特性下的四旋翼飞行器轨迹跟踪控制, 基于非线性滑模控制技术, 结合条件积分思想及Lyapunov稳定性理论设计了一种位姿双环条件积分滑模控制器。在获得四旋翼非线性动力学模型后对其进行线性化, 简化被控对象数学模型, 提高控制器设计效率。利用条件积分滑模控制律设计了位置环和姿态环的轨迹跟踪控制器, 实现了控制系统的全局渐近稳定。通过仿真算例验证了所设计控制器的有效性, 结果表明: 与其他控制器相比, 所设计的控制器具有较高的控制精度、较强的抗干扰性及鲁棒性, 可有效抑制系统振动、消除静态误差,并实现四旋翼飞行器的高性能轨迹跟踪。
四旋翼飞行器 轨迹跟踪 条件积分滑模 位置环 姿态环 quadrotor aircraft trajectory tracking conditional integral sliding mode position loop attitude loop
