997 resultados para 366.2487


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为了研究(111)衬底的特性以及实现等边三角形微腔激光器,利用金属有机化学气相淀积(MOCVD)研究了(111)A InP衬底上InGaAsP外延层的表面形貌和光学特性。考虑到(111)A InP衬底的悬挂键密度比较低,在生长过程中有意提高了V/III比。通过扫描电子显微镜(SEM)和光荧光(PL)谱分别研究了外延层的表面形貌和光学特性。实验发现,表面形貌和光学特性随V/III比和温度的变化非常大。最佳V/IlI比和温度分别为400和625℃。

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数值模拟了增益钳制SOA(GC-SOA)的波长转换过程,分析了GC-SOA实现波长转换的原理.首次发现了GC-SOA波长转换中类似接通延迟的现象,这种现象将限制GC-SOA在高速波长转换中的应用.

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文中就如何增大耦合效率和工艺容差的问题作了具体的分析,在此基础上,评述了现有的几种能够获得较低插入损耗的光纤和波导的固定联接技术。

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An ultracompact 3-dB coupler is designed and fabricated in silicon-on-insulator,based on 12 line tapered multimode interference(MMI) coupler.Comparing with the conventional straigth MMI coupler,the device is-40% shorter in length.The device exhibits uniformity of 1.3dB and excess loss of 2.5dB

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从材料的生长、器件结构的选择等方面对1.55μm锗光电探测器的研究进展进行了综述,对Ge量子点共振腔增强型光电探测器的应用前景进行了探讨与展望。

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在Si衬底上自组装生长纳米尺度的Ge量子点,由于三维量子限制效应的贡献,能够在能带结构上对 Si、Ge天然材料的间接带特性实施准直接带结构的改性,使激子行为和带间复合跃迁得到大幅度增强,同时Ge量子点的可控有序相关排列还有助于发展新一代的Si基电子波量子器件.文章回顾了自20世纪80年代末至今Ge/ Si量子点生长研究的重要进展,对其潜在的重要应用作出了评述.结合作者自己的研究结果,着重介绍了Ge量子点的生长动力学及其形态的演变过程,指出自组装生长的Ge/Si量子点属Ⅱ型能带结构,其发光效率比一维量子阱有很大增强.探讨了用模板衬底实现对Ce量子点尺寸和分布的有序可控生长方法与途径.

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采用张应变量子阱结构,生长了光放大器材料。利用宽接触激光器TE和TM模的输出功率曲线判断并调整量子阱材料的应变量,得到了偏振灵敏度较低的光放大器结构。

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A novel structure of MMI coupler with different background refractive index has been designed. With stronger optical confinement in multimode waveguides, more guided modes are excited to improve imaging quality. Two-dimensional finite difference beam propagation method (2-D FDBPM) was used to simulate this new structure and had proven that its imaging quality, in terms of power uniformity and excess loss, is much better than conventional structure. This structure can be applied in SOI rib waveguides by deep etching method.

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报道了由2N个1×N多模干涉马赫-曾德尔光开关组成的N×N光开关阵列结构,分析了这种结构的开关阵列优势和局限性。用场传输矩阵方法建立了1×N多模干涉光开关的光场传输方程。给出了光开关阵列从任一输入端输入、从任一输出端正输出时阵列开关的工作条件。在上述原理及理论基础上分析了4×4光开关阵列的结构和工作条件。

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分析了SOI(silicon-on-insulator)2×2电光开关工作时热光效应对等离子色散效应的影响。采用二维半导器件模拟器PISCES-Ⅱ对器件进行模块。结果表明,热光效应对等离子色散效应的影响与调制区长度密切相关,当调制区长度较短时,热光效应的影响不容忽视;当调制区长度大于500μm时,这种影响可以忽略不计

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随着光纤通信技术的不断发展,作为光分插复用(OADM)和光交叉互联(OXC)核心器件的光开关作用日益突出。文章从开关单元结构、材料及调制机理三个角度对波导开关进行了划分,阐述了波导开关的基本原理以及当前的研究进展,对面临的一些技术挑战进行了分析,并提出了自己的观点。

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本文分析了用白噪声产生高速真随机码的基本原理。用HP346C宽带白噪声源和二级带有判决电路的D解发器,产生了高速非归零真随机码,避免了由亚稳态造成的延时抖动。

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报道了利用Si基键合技术和化学机械抛光工艺制作的垂直结构的Fabry-Perot可调谐滤波器,调谐机理为pn结正向注入电流引起的热光效应。调谐范围可达23nm,响应时间约为300 μs,并给出了获得更快响应和更低能耗的热光和电注入可调谐滤波器件结构改进方案。

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The band structure of 2D photonic crystals (PCs) and localized states resulting from defects are analyzed by finite-difference time-domain (FDTD) technique and Pade approximation. The effect of dielectric constant contrast and filling factor on photonic bandgap (PBG) for perfect PCs and localized states in PCs with point defects are investigated. The resonant frequencies and quality factors are calculated for PCs with different defects. The numerical results show that it is possible to modulate the location, width and number of PBGs and frequencies of the localized states only by changing the dielectric constant contrast and filling factor.

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提出了一种新的紧缩型SOI多模干涉(MMI)光开关。开关由单模输入输出波导和MMI耦合器组成。通过在多模波导区域引入调制区,利用Si的等离子色散效应(PDE)改变调制区的折射率来实现开关动作。用FD-BPM方法对开关的工作原理和性能进行了模拟与分析。结果表明,光开尖良好的综合性能,而整个开关的长度只有7mm。