Flexible integration of optical switch with optical power splitting and attenuating functions for optical fiber-based networking applications

A flexible integration of optical switch with optical power splitting and attenuating functions has been proposed to optimally serve optical fiber-based networking applications. In this switch, an etched binary-slope sidewall reflector is electrostatically actuated in and out of the plane to manipulate optical signals between input and output optical fibers. The fabrication process is a simple combination of a bulk-silicon micromachining process and silicon-to-glass anodic bonding where fiber alignment grooves, reflectors and actuators are fabricated on the same silicon substrate. Ball-lensed fibers are assembled with the device to achieve high coupling efficiency. Performances of the fabricated devices are measured and discussed. The switching time is less than 9 ms at 31 V. The excess loss of the device is less than 3 dB and the controllable attenuation range is up to 38 dB at 139 V, respectively. Moreover, polarization-dependent loss is less than 0.7 dB in the whole attenuation and splitting range.     

Ultrafast dynamics and temperature effects on the quantum efficiency of the ring-opening reaction of a photochromic indolylfulgide

The ultrafast ring-opening reaction of the molecular switch 1,2-Dimethyl-3-indolylfulgide dissolved in acetonitrile is investigated by temperature dependent quantum efficiency measurements and time-resolved transient absorption spectroscopy in the ultraviolet and visible spectral range. The photoreaction is found to be thermally activated with an activation energy of about 1640 cm^− 1. The transient absorption signal is bi-exponential with the time constants τ₁ = 0.7 ps and τ₂ = 12 ps. The fast time constant is due to solvation dynamics, while the main component τ₂ is attributed to the excited state lifetime and product formation. A long-lived intermediate state in the photoreaction can be excluded.     

基于磁开关的全固态、高功率、长脉冲发生器的初步研究

大多数电容储能型脉冲功率装置的共同特点是采用了气体开关, 由于气体绝缘恢复的限制和电极的烧蚀, 使得其重复频率都不太高, 而且寿命有限. 而目前广泛研究的磁脉冲压缩技术在脉冲功率系统的长寿命、高平均功率和高重复频率运行方面具有很大的应用前景. 通过对BOOST电路、LC谐振电路和磁脉冲压缩电路详细的理论分析和计算机模拟, 设计了由BOOST电路, LC谐振电路, 脉冲变压器, 磁压缩系统, 负载五大部分组成的脉冲发生器电路系统模型, 使用Pspice软件对系统进行了模拟、优化, 得到了电压幅值为55kV, 脉宽为500ns的输出脉冲.     

衍射扭曲高斯-谢尔模型光束在远场的光谱移动和光谱开关

从部分相干光的传输理论出发,研究了被光阑衍射扭曲高斯-谢尔模型光束远场的光谱变化规律。结果表明,扭曲高斯-谢尔模型光束在远场也会出现光谱移动和光谱开关效应。与衍射高斯-谢尔模型光束情况相比,光谱移动和光谱开关效应不仅与光束空间相关性、截断参量和源光谱谱宽有关,光束的扭曲因子也会对衍射扭曲高斯-谢尔模型光束远场的光谱移动和光谱开关效应产生影响。通过数值计算结果详细讨论了光束扭曲因子影响衍射扭曲高斯-谢尔模型远场光谱的规律。     

一种微型光开关的设计与仿真分析

介绍了一种新型的聚酰亚胺(PI)悬臂梁式电磁驱动微机电系统(MEMS)光开关,并对其总体结构进行了设计与仿真分析.运用有限元分析的方法,设计了永磁体的最佳尺寸并优化了悬臂梁的结构;分析了聚酰亚胺悬臂梁的扭转力、电磁力与挠度的关系.当输入电流为75 mA时,聚酰亚胺悬臂梁达到平衡时的挠度约为1.02 mm,能够满足器件转换光路的要求.     

单电荷带电态对分子线输运特性的影响

利用Su-Schrieffer-Heeger(SSH)模型及平衡格林函数方法研究了一维分子线基态与带电态下的电子输运特性.研究发现,分子线基态对应较高的阻态,而带电态对应较低的阻态.分子线在带电态(低阻态)与基态(高阻态)之间转换,可使体系具有导电开关的功能,这与近来实验上观察到的一些现象相符.进一步讨论了链长对分子线输运特性的影响.     

光谱开关与多色光场的奇点光学效应

推导出多色高斯光束和高斯-谢尔模型光束通过杨氏实验双缝传输的谱强度公式.对完全空间相干光和部分空间相干光照明杨氏实验装置出现的光谱开关作了详细研究,并判断其是否属于奇点光学效应. 结果表明：多色场奇点光学效应的判据应当是光谱开关出现时的谱强度极小值S_min=0,而不是总光强极小值I_min=0. 当用多色高斯-谢尔模型光束照明杨氏实验装置时,在近场和远场产生的光谱开关都不属于奇点光学效应. 当用多色高斯光束照明杨氏实验装置时,只有远场产 关键词： 光谱开关 奇点光学效应 完全相干和部分相干 多色光场     

聚合物微环电光开关的模拟和优化

利用耦合模理论、电光调制理论和微环谐振理论,提出一个完善合理的聚合物微环电光开关的器件模型,并给出了可用以分析微环谐振过程的光强传递函数,据此在谐振波长1 550 nm下对该器件进行了模拟和优化.结果表明：微环波导芯截面尺寸为1.8×1.8 μm2,波导芯与电极间的限制层厚度为1.1 μm,电极厚度为0.15 μm,微环半径为15.2 μm,微环与信道间的耦合间距为0.16 μm,光绕微环转300 圈即可形成稳定的谐振状态,此时的谐振时间约为147.4 ps.不加电压时,下信道的插入损耗约为0.8 dB,上信道的串扰约为－26 dB;当取工作电压等于19.7 V为开关电压时,上信道的插入损耗约为0.34 dB,下信道的串扰约为－20 dB.     

Visible-Light Photoswitching by Azobenzazoles

Three visible-light responsive photoswitches are reported, azobis(1-methyl-benzimidazole) ( 1 ), azobis(benzoxazole) ( 2 ) and azobis(benzothiazole) ( 3 ). Photostationary distributions are obtained upon irradiation with visible light comprising approximately 80 % of the thermally unstable isomer, with thermal half-lives up to 8 min and are mostly invariant to solvent. On protonation, compound 1 H⁺ has absorption extending beyond 600 nm, allowing switching with yellow light, and a thermal half-life just under 5 minutes. The two isomers have significantly different pK_a values, offering potential as a pH switch. The absorption spectra of 2 and 3 are insensitive to acid, although changes in the thermal half-life of 3 indicate more basic intermediates that significantly influence the thermal barrier to isomerization. These findings are supported by high-level ab initio calculations, which validate that protonation occurs on the ring nitrogen and that the Z isomer is more basic in all cases.     

Profitability of online order fulfillment in multi-channel retailing

Store-based retailers have been concerned about the high fulfillment costs and low gross margins of their online sales. This paper incorporates such issues in a non-linear mixed-integer profit maximization model of the online order fulfillment process for multi-channel retailers. A solution approach based on an iterative outer-approximation technique is developed. Using empirical data from a large U.S. retailer, the profitability of different options used by multi-channel retailers to fill online orders is evaluated. Managerial insights are developed through a factorial research design that highlights the effect of relevant logistics processes and fulfillment methods on the profitability of online sales for retailers.