一种特殊的双包层圆柱光波导的研究

本文研究了一种双包层阶跃型光波导，内包层的折射率大于芯及外包层的折射率，因而可作为导波层。文中严格地推导了柱坐标下该光波导的特征方程，详细计算了ＴＥ波和ＴＭ波的传播常数、场分布及功率分布；作出了相应的曲线，表明了导波层的厚度、折射率及工作波长对此类光波导传播特性的影响。     

一种特殊的双包层圆柱光波导的研究

本文研究了一种双包层阶跃型光波导，内包层的折射率大于芯及外包层的折射率，因而可作为导波层。文中严格的推导了柱坐标下该光波导的特征方程，详细计算了ＴＥ波和ＴＭ波的传播常数、场分布及功率分布；作出了相应的曲线，表明了导波层的厚度、折射率及工作波长对此类光波导传播特性的影响。     

基于光栅波导共振耦合的传感器特性研究

该文设计了一种基于光栅波导共振角耦合的生物传感器,通过光栅波导模式谱变化检测传感器表面有效折射率变化的方式,实现了传感器表面附着物的精确检测。并在平板介质光波导理论基础上,推导了三、四层结构理论模型,实验得到了入射角与检测溶液折射率及入射角与分子膜层厚度间的变化关系。结果表明,光栅波导共振角耦合生物传感器入射角与待测溶液折射率存在良好的线性关系,并具有较高灵敏度,精度可达0.01(°)/nm。通过该方法制作出无标记的生物传感器,能广泛应用于生物分子检测,尤其适合蛋白质分子生物检测。     

改进长周期波导光栅折射率传感特性的研究

提出了一种附加高折射率覆盖层的长周期波导光栅折射率传感器结构.通过模拟外折射率变化所引起的高阶模式等效折射率的改变以及该高阶模式与基模相耦合的谐振波长的漂移,研究了长周期波导光栅对外界环境折射率的传感特性.模拟表明,高折射率外覆盖层的加入会使得原有的覆盖层高阶模式发生重组,高阶模式等效折射率和模式耦合的谐振波长随之发生跳变.此时,长周期波导光栅外折射率传感器的敏感度和工作范围将极大地提高.     

基于光子晶体波导的折射率传感器的灵敏度优化设计

通过研究波导两侧缺陷处的折射率对二维光子晶体波导透射光谱的影响,提出一种提高折射率传感器灵敏度的方案。计算结果表明光子透射带上边沿的偏移量与传感区折射率的大小存在一定关系,在相同的折射率变化量下通过改变波导两侧缺陷处圆孔的相关几何参数可极大提高光子透射带上边沿的偏移量,即提高折射率传感器的灵敏度。通过优化设计,传感器的灵敏度由折射率变化区间0.0~1.0的55 nm/RIU(RIU表示折射率单元)与1.1~2.0的36 nm/RIU分别提高到对应的405 nm/RIU以及222 nm/RIU。     

光学传感器捕获滥用药物者

在分子水平上探测生化反应的光学传感器可在数分钟内发现运动员是否滥服药物。这项技术相对于花费数小时才能完成的传统的血液或尿液样品的化学分析来说是个极大的改进。除了节省时间外，ＬａｂｓｙｓｔｅｍｓＡｆｆｉｎｉｔｙｓｅｎｓｏｒｓ公司设计的新型生物传感器比现在使用的传感器的灵敏度高出三倍，该公司期望在不久的将来完成该传感器。Ｌａｂｓｙｓｔｅｍｓ公司目前的生物传感器是基于共振镜设计的，其中６７０ｎｍ的激光束入射到一个通过低折射率间隔到高折射率波导耦合的尺寸为９×７×６ｍｍ~３棱镜。当光束到达棱镜某一表面的…     

高折射率材料填充的光子晶体光纤传输谱分析

利用有限差分法,研究了一种在包层小孔中填充可变折射率材料的新型光子晶体光纤的传输特性,并讨论了其在传感器设计方面的应用前景.分别模拟了包层孔为单圈、两圈、三圈结构下的光纤传输谱,在两圈孔的情况下,找到了合适的工作波长区间,并发现该工作区间的位置对于填充材料的折射率表现得很敏感,且呈近似线性关系.该折射率在1.48～1.8区间内每变化0.01,导波区间位置平均移动24 nm.结论表明,与传统的光波导折射率传感器相比,这种新型光子晶体光纤折射率传感器具有测量范围较大,灵敏度较高的优点.     

波导相位调制器的电极设计

波导相位调制器是由电光扩散波导、两侧配置平行的直条形电极构成。当电极上外加电压后,晶体表面产生局部电场,引起波导折射率的变化,导致波导模传播常数的改变,最终使导波模的相位发生变化。调制效率决定于光场和电场的相互作的交迭程度,     

光波导生物化学传感器研究进展

光波导具有结构简单,体积小,耐腐蚀,电绝缘性好,便于集成等特点.光波导对折射率、吸收以及放光过程（例如：化学发光或荧光）的变化敏感.这些变化对波导中传输的光起到了调制作用,可利用光波导的这些特性制成各类传感器.其中光波导生物化学传感器是将光波导技术与化学、生物工程技术相结合,它必将会在生物化学领域中发挥重要作用.本文综述了已经研制出的几种类型的光波导生物传感器,并对其特性进行了比较.     

简明消息

以激光生产经济的通信系统法国通信研究中心用紫外激光可以将连接激光器、传感器和电子线路所需的光波导印制在衬底上。激光束扫描穿越薄膜产生光波导激光辐射用来改变生长在衬底表面薄膜的折射率,形成波导。该工艺不需要任何光致抗蚀剂和蚀刻剂,就可望生产出较经济的通...     

基于双面金属波导的纳米磁流体磁调制

设计了一种双面金属包覆波导,其中作为样品室的导波层厚度达到毫米量级.在波导腔体中注入浓度为0.15%的水基四氧化三铁纳米磁流体,采用波长为860 nm的红外激光束小角度(小于5°)入射到该波导金属耦合层上,以激发波导中的超高阶导模,使纳米磁流体处于光波导的振荡场中.根据超高阶导模的高灵敏特性,对磁流体施加10 mT的调制磁场,检测到纳米磁流体的磁光信号上升和下降时间为2 ms.     

Low Loss Star Coupler Concept for AWGs in Rib Waveguide Technology

We introduce a new concept for a tapered transition between waveguides and a free propagation region (FPR) for rib waveguide technology. The optical field is pressed downwards to the lower part of the guiding layer by tapering off the waveguide. The subsequent FPR is also etched down to the lower part of the guiding layer, which results in an adiabatic transition from the waveguide to the slab. Arrayed waveguide gratings, designed with this technique, were fabricated in silicon-on-insulator and showed a reduction in insertion loss of about 2.5 dB     

A simple laterally tapered waveguide for low-loss coupling tosingle-mode fibers

Low-loss coupling between semiconductor photonic devices and single-mode fibers is achieved using a simple InP/InGaAsP tapered waveguide. The proposed simple structure has a small and nearly square guiding core at its output facet. In this structure, the output field has a non-Gaussian profile, but low-pass filter coupling can be achieved by optimizing the design of the guiding core sizes. The waveguide is composed of a laterally tapered InGaAsP guiding layer and an InP cladding region on an InP substrate, facilitating integration of the waveguide with active devices using conventional processes. The waveguide is shown to have a total insertion loss of 2.6 dB, including a coupling loss of 0.9 dB and large ±2.5-μm misalignment tolerance in lateral and vertical directions with single-mode filters     

基于曲折网格表面的二维通信技术

二维通信系统(Two-dimensional Communication System, 2DCS)是一种以物体表面为通信介质的新型 通信技术,可以提供无线供电以及安全、高速的数据传输服务。为了改善二维通信中的供电性能,文中提出了一种 增强功率传输性能的二维通信导波板,该导波板包含三层:导电层、介质层和具有曲折网格的表面层。微波通过同 轴导波耦合器馈入二维通信导波板,可以在呈电感性的曲折网格表面任何一点耦合出表面层。经电磁仿真和实际 测试验证,与以前的二维通信导波板相比,曲折网格结构和阻抗匹配的同轴导波馈电器改善了二维通信导波板的传 输性能和电磁场分布的空间均匀性。     

大带宽集成光学电场传感器的频率响应特性分析

采用马赫-曾德尔光波导干涉仪与锥形天线阵列,研制了基于铌酸锂（LiNbO3）结构、可用于电力电场测量的大带宽电场传感器,并通过实验对传感器性能进行了测试。结果表明,该传感器在10kHz～18GHz的大带宽范围内,频响特性波动小于±10dB,最小可测电场强度达到0.4V/m,可测量场强达103V/m的纳秒脉冲电场。     

Use of Reversal Nanoimprinting of Nanoparticles to Prepare Flexible Waveguide Sensors Exhibiting Enhanced Scattering of the Surface Plasmon Resonance

A flexible surface plasmon resonance (SPR)‐based scattering waveguide sensor is prepared by directly imprinting hollow gold nanoparticles (NPs) and solid gold NPs onto flexible polycarbonate (PC) plates—without any surface modification—using a modified reversal nanoimprint lithography technology. Controlling the imprinting conditions, including temperature and pressure, allows for the fine adjustment of the depths of the embedded metal NPs and their SPR properties. This patterning approach exhibits a resolution down to the submicrometer level. A 3D finite‐difference time domain simulation is used to examine the optical behavior of light propagating parallel to the air/substrate interface within the near‐field regime. Consistent with the simulations, almost an order of magnitude enhancement in the scattering signal after transferring the metal NPs from the glass mold to the PC substrate is obtained experimentally. The enhanced signal is attributed to the particles' strong scattering of the guiding‐mode waves (within the waveguide) and the evanescent wave (above the waveguide) simultaneously. Finally, the imprinting conditions are optimized to obtain a strongly scattering bio/chemical waveguide sensor.     

论证电子回旋脉塞动力学理论的两种方法

近几年来,由刘盛纲(1979,1981)发展的以回旋中心坐标系中场的局部展开为基础的电子回旋谐振受激辐射的动力学理论,已形成一个理论体系。本文简要地阐述了建立回旋中心坐标系的数学依据和物理解释。文中通过回旋中心坐标系法和波导轴坐标系法,分别对单动量轴对称电子注和圆波导中TEmn模式场的互作用进行了计算,严格地导出了相同的色散方程。文中还指出了万遂人(1995)文章中存在的若干问题。     

Graded effective index planar polymer waveguides

A dispensed polymer waveguide with a parabolic surface is shown to exhibit graded index waveguide behavior for each of the discrete vertical modes of the polymer layer due to the lateral variation of the effective indexes of the modes. Air-clad waveguide losses are less than 0.7 dB/cm. Beam propagation simulations show excellent agreement with recorded images of oscillating guided beams. These graded effective index waveguides may be useful in high-speed, large scale optical interconnections and coarse wavelength division multiplexing (WDM) integrated optics applications     

Design and Analysis of Refractometer Based on Bend Waveguide Structure with Air Trench for Optical Sensor Applications

This study proposes a novel optical sensor structure based on a refractometer combining a bend waveguide with an air trench. The optical sensor is a splitter structure with a reference channel and a sensing channel. The reference channel has a straight waveguide. The sensing channel consists of a U‐bend waveguide connecting four C‐bends, and a trench structure to partially expose the core layer. The U‐bend waveguide consists of one C‐bend with the maximum optical loss and three C‐bends with minimum losses. A trench provides a quantitative measurement environment and is aligned with the sidewall of the C‐bend having the maximum loss. The intensity of the output power depends on the change in the refractive index of the measured material. The insertion loss of the proposed optical sensor changes from 3.7 dB to 59.1 dB when the refractive index changes from 1.3852 to 1.4452.     

Slow propagation of electromagnetic waves in a dielectric slab waveguide with a left-handed material substrate

The dispersion properties of the guided modes propagating along a dielectric slab waveguide with a left-handed material substrate are studied. It is shown that both the oscillating and surface modes can propagate very slowly along such a waveguide if the thickness of the core layer is chosen appropriately. The propagation speed of the guided waves can even approach zero and this slow propagation is illustrated with an finite-difference time-domain simulation in a tapered waveguide. The influence of the material loss on the slow propagation is also discussed.