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A Novel Design of Grating Couplers for Efficient Broadband Coupling between Silicon-on-Insulator Nanophotonic Waveguides and Fibres 下载免费PDF全文
A novel design of out-of-plane grating couplers is proposed for coupling between silicon-on-insulator nanophotonic waveguides and single-mode fibres. The coupler with the first-order diffraction coupling to the optical fibre is actually a second-order reflected grating with two times of period of the first-order grating. To enhance outcoupled power, a back hole is designed to form in the silicon substrate and a kind of metals is placed on the top acting as a reflection layer. The coupler is optimized using coupled-mode-based simulations, showing that the coupling efficiency to and from tapered optical fibre can be as high as 85% with 1dB bandwidth about 23 nm. 相似文献
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AWG中波导间耦合造成的相位畸变的分析 总被引:1,自引:1,他引:0
用(1,1)阶Pad啨近似的广角BPM计算了阵列波导光栅(AWG)中由于阵列波导间耦合造成的相位畸变以及由于相位畸变引起的相位误差分别考虑了光从中心/非中心输入波导入射两种情况结果表明,波导间的耦合会造成显著的相位畸变,但由此引起的相位误差却很小,光从中心输入波导入射时对应的相位误差10-3rad,从非中心输入波导入射时的相位误差约为10-2rad针对波导阵列边缘效应引起的相位畸变,设计AWG结构时,在阵列部分两侧增加了边缘辅助波导结构,从而消除了边缘效应,使得边缘阵列波导对应的相位误差从10-1rad量级减小为10-3(10-2)rad量级. 相似文献
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M. M. Shabat M. A. Abdel-Naby Y. S. Madi D. Jäger 《International Journal of Infrared and Millimeter Waves》1999,20(4):725-735
We present here two methods of analysis of the complex moving waveguide. One approach is a numerical technique based on Davidenko's method, the other is a perturbation method. Numerical results by Davidenko's method are compared with these obtained from the perturbation method. It is found that the results of the perturbation method are in a good agreement with the numerical one. A comparative study of the propagation and attenuation characteristics of the stationary and moving waveguides has also been investigated and discussed. These results could be used in designing many optical moving sensors. 相似文献
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Hao Xu 《Letters in Mathematical Physics》2012,101(3):239-264
We prove an explicit formula of the Berezin star product on K?hler manifolds. The formula is expressed as a summation over certain strongly connected digraphs. The proof relies on a combinatorial interpretation of Engli??? work on the asymptotic expansion of the Laplace integral. 相似文献
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Weinvestigate thephase transition of the three-state Potts model in an analytical approachthe generalized cumtilant expansion with the effective mean field Itypothesis. We find a first order phase transition in the three-dimensional three-state Pot ts model with ferromagnetic nearest neighbor (nn) coupling. For the model with antiferromagnetic next-to-nearest neighbor (nnn) coupling, pe find a first order transition when tlle relative strength of the nnncoupling γ is fixed to -0.2. The critical values given by this method are also in agreement with the recent high statistics Monte Carlo results. 相似文献
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WANG Zhong-Jie CHEN Feng 《理论物理通讯》2007,47(4):725-727
The interaction of a single three-level trapped ion with two laser beams has been studied theoretically. With application of two successive unitary transformations, an analytical solution to this quantum system has been obtained. 相似文献
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随着引力波探测以及对中子星质量与半径的高精度测量,中子星作为超新星爆发的剩余产物正吸引着相关领域的高度关注。在中子星的内核部分,诸如超子之类的奇异自由度有可能会出现从而形成超子星。本工作在相对论平均场模型框架下研究由核子与轻子构成的中子星以及包含超子的超子星。采用目前常用的非线性相对论平均场以及密度依赖的相对论平均场参数研究了超子对超子星质量、半径、潮汐形变等性质的影响。最后讨论了介子与超子的耦合常数对超子星性质的影响,发现当矢量介子与超子耦合系数较强时,利用现有的相对论平均场模型参数可以获得大质量的超子星。 相似文献
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S.K. Islam V. Srinivasan F.C. Jain 《International Journal of Infrared and Millimeter Waves》2001,22(12):1813-1824
An analytical two-dimensional model for an n-channel SiGe MOSFET is presented. In this paper a three-region model for SiGe is developed. The space charge region under the gate has been divided into three regions and the two-dimensional potential distribution is found by choosing appropriate boundary conditions for the drain, source and depletion regions. The analytical model predicts unity current-gain cut-off frequency (f
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从超短脉冲光束的傍轴传输方程出发,运用傅里叶变换和相关数学算符的对易性,得到了超短脉冲径向偏振光束的解析表达式,该解可适用于任意脉冲驱动的径向偏振光束.基于该解析表达式并结合具体例子,讨论了超短脉冲径向偏振光束在自由空间中的传输性质.结果表明,在传输过程中时空耦合主要体现在光束边沿的脉冲延迟.这一效应导致了脉冲不同时间位置处横向光强分布随传输的变化,以及脉冲前后沿关于束腰的不对称性.本文的方法同样适用于得到超短脉冲方位角偏振光束的解析解和传输性质. 相似文献
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从超短脉冲光束的傍轴传输方程出发, 运用傅里叶变换和相关数学算符的对易性, 得到了超短脉冲径向偏振光束的解析表达式.该解可适用于任意脉冲驱动的径向偏振光束. 基于该解析表达式并结合具体例子,讨论了超短脉冲径向偏振光束在自由空间中的传输性质. 结果表明, 在传输过程中时空耦合主要体现在光束边沿的脉冲延迟. 这一效应导致了脉冲不同时间位置处横向光强分布随传输的变化, 以及脉冲前后沿关于束腰的不对称性. 本文的方法同样适用于得到超短脉冲方位角偏振光束的解析解和传输性质. 相似文献
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Batch Assembly Micro-Ball Lens Array for Si-Based Optical Coupling Platform in Free Space 总被引:1,自引:0,他引:1
The paper presents novel concepts of batch fabrication of micro-ball lens array technology integrated on the silicon-based wafer which can improve the appropriate distance for optical fiber coupling. The silicon-based optical coupling platform consists of a self-parking framework (including flat-topped mesa and intersection of two v-grooves) and micro-ball lens array for optical fiber coupling purposes. The structure of optical coupling platform is able to improve the distance between fiber and micro-ball lens and to increase coupling efficiency. Optical measurement reveals an insertion loss below 2.5 dB with wavelength 635 nm in singlemode fiber. The micro-ball lens array is batch fabricated by polymeric material and thick photoresist, and then bonded onto a flat-topped mesa that adjoins to the v-groove. The corner compensation offers a method to fabricate the flat-topped mesa in the intersection of two v-grooves. This fabrication process not only provides accurate coupling distance between fibers and micro-ball lens, but also reduces micro-assembly cost.This paper was originally presented at the 2001 International Conference (2nd Joint OSJ-SPIE Conference) on Optical Engineering for Sensing and Nanotechnology, ICOSN 2001 which was held June 6-8, 2001 at the Pacifico-Yokohama Conference Center, Yokohama, Japan. 相似文献
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We investigate the structure of a proton in free space by using the quark-meson coupling model. In the model, a proton in free space is regarded as a MIT bag with σ, ω and ρ meson fields and the Coulomb potential. With the boundary condition at bag surface, the wave functions of u and d quarks and potentials are calculated self-consistently. 相似文献
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We propose a modified formula which is used to determine the coupling parameter C in the Hamiltonian of the single-j shell. In comparison with the previously known formula, the new formula improves the agreement between the intruder single-j levels and the Nilsson ones. For studies of chiral bands within the particle rotor model, the new coupling parameter will considerably influence the energy splitting between the doublet bands. 相似文献
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An equivalence is found between the BEG model and an Ising model with cross and four-spin interaction on square lattice under a well-known restriction eK cosh J = 1. 相似文献