单模与多模光纤耦合器的光束合波

现有的光纤耦合器在作为分波器使用时具有较低的插入损耗,在作为合波器时插入损耗较大,为实现低损耗合波目的,提出一种由单模与多模光纤共同构成的混合型光纤耦合器。利用耦合波方程理论分析其工作原理,计算机模拟其耦合过程。采用熔锥法制作工艺,完成单模与多模光纤耦合器的制作,实验结果与理论模拟相吻合;该器件单模到多模光纤的耦合效率、多模到多模光纤的耦合效率均在90％以上,实现了两路光束的功率合波。作为低插入损耗合波器件可广泛应用于光通信以及双包层光纤激光器抽运光的注入。     

基于CsPbBr_(3)纳米晶掺杂硫醇-烯聚合物的荧光太阳集光器制备及集光性能EI北大核心CSCD

荧光太阳集光器在光伏建筑一体化方面的潜在应用受到了广泛关注。本文采用CsPbBr_(3)纳米晶作为集光器的发光中心,采用硫醇-烯聚合物作为集光器的透明光波导基质。通过荧光发射谱、吸收谱以及荧光寿命谱等对集光性能进行研究,发现将CsPbBr_(3)纳米晶掺入硫醇-烯聚合物后,发光峰位蓝移了11 nm、半高宽展宽了20.4 nm,这可归因于硫醇-烯聚合物基质的介电约束效应。同时,硫醇-烯聚合物基质大幅提高了CsPbBr_(3)纳米晶的发光稳定性。当CsPbBr_(3)纳米晶在硫醇-烯聚合物基质中的掺杂浓度为5.6%时,荧光太阳集光器的集光效率可达8.9%。采用商用的多晶硅太阳能电池耦合在荧光太阳集光器的边缘,在标准AM1.5的太阳光照条件下,器件开路电压为0.47 V,短路电流密度为7.14 mA/cm ^(2),填充因子为24.01%,光电转换效率为2.30%。     

全息太阳能集光器

研究了全息太阳能集光器的机理 ,指出使用全息太阳能集光器 ,可大大提高太阳能热水器的光热转换效率。     

球形光纤端面效应及其应用

本文介绍了球形光纤端面的制作方法,采用射线理论和等效透镜法分析了圆球形端面多模光纤的端面效应,并给出了两个不同端面多模光纤之间耦合的实验结果。结果表明：圆球形端面光纤具有聚光特性,与平端面相比,使用圆球形端面光纤不仅可以提高光器件之间的耦合效率,而且增大了它们之间的耦合距离,利于光路调试;可广泛应用于光源与光纤、光纤与光纤、光纤与探测器之间的耦合。     

大功率激光二极管与多模光纤耦合效率分析

提出了一种用于大功率激光二极管与多模光纤耦合的新颖的铲形整形系统，详细分析了铲形光纤端头不同的切割角度、切割深度以及耦合距离对激光二极管与铲形光纤耦合效率的影响。提出了一种计算该系统耦合效率的方法，同时给出了耦合效率的计算实例，得出了可以最大程度地提高铲形耦合头作用的优化参量。     

脉冲电场测试中的激光供电技术

为解决脉冲电场测试系统中的供电问题，设计了一套激光光纤供电系统，该系统由激光器、多模光纤及光电池构成。重点研究了激光器与光纤的耦合问题，设计了透镜系统对激光器输出光束进行准直和压缩。通过MOCVD法研制了GaAs光电池，并制作了椭球形"光伏眼"来提高光电转换效率。仿真和实验表明:采用透镜耦合时，激光器与光纤的耦合效率可达80%以上，远远高于直接耦合时的16%，改进后的"光伏眼"耦合效率相比直接耦合时提高了54.5%，激光供电系统的转化效率在40%以上。该系统的研制为解决脉冲电场的供电问题提供了一种方案。     

多模光纤放大器输出光分析

根据不同的泵浦方式,对多模光纤放大器运用多模速率方程组,采用四阶龙格-库塔法数值计算和分析了在不同泵浦方式下的泵浦效率和信号光在光纤放大器中的传输、放大行为,并研究了在光纤放大器光纤长度有微小变化(mm量级)的情况下,输出光的光束质量与光纤长度的关系。结果表明:输出信号光的光束质量因子随光纤长度微小变化而呈准周期变化,周期与信号光耦合入光纤放大器的本征模式间的传播常数差有关。     

埋入光纤挠性基板的光电耦合模块设计

为了提高埋入光纤挠性基板光电互联系统中激光束与光纤之间的耦合效率,设计了一种可分离式的高效光电耦合模块。对耦合模块的结构尺寸进行了设计,并运用Matlab软件分析了激光束经过45°全反射镜时的能流变化情况;针对芯径为62.5μm、数值孔径为0.25的多模光纤,利用Zemax软件仿真模拟光纤耦合系统,并用正交下降法优化耦合系统结构,将单路波长为1 310 nm、输出功率为1 W的垂直腔面激光束耦合进光纤。分析结果表明,耦合效率与轴向偏差、角向偏差成中心对称分布,当制造误差最大时,耦合效率达到79.37%,耦合损耗为1. 00 d B。该光电耦合模块具有较高的定位误差,最高耦合效率可达85.35%,最低耦合损耗为0.69 d B。     

基于非球面透镜的空间光场光纤耦合系统研究

针对全光纤激光雷达中空间光场与单模光纤的耦合问题,设计了基于非球面透镜的望远镜光纤耦合系统.利用ZEMAX软件以单模光纤耦合效率为优化目标对其结构参量进行优化设计,然后分别用LED和激光器作为光源进行初步实验,比较直接耦合和非球面透镜耦合效果.实验结果表明,采用非球面透镜耦合可使多模光源的耦合效率比直接耦合增加约47%,与仿真结果45%非常接近,且不同芯径耦合光功率之比大略等于芯径比平方;而该耦合方式可使单模光源的耦合效率增加约20%,且耦合进不同小芯径光纤的耦合效率之比约为其芯径比平方的2.4倍,这对构建全光纤转动喇曼激光雷达系统具有重要意义.     

基于非球面透镜的空间光场光纤耦合系统研究

针对全光纤激光雷达中空间光场与单模光纤的耦合问题,设计了基于非球面透镜的望远镜光纤耦合系统.利用ZEMAX软件以单模光纤耦合效率为优化目标对其结构参量进行优化设计,然后分别用LED和激光器作为光源进行初步实验,比较直接耦合和非球面透镜耦合效果.实验结果表明,采用非球面透镜耦合可使多模光源的耦合效率比直接耦合增加约47％,与仿真结果45％非常接近,且不同芯径耦合光功率之比大略等于芯径比平方;而该耦合方式可使单模光源的耦合效率增加约20％,且耦合进不同小芯径光纤的耦合效率之比约为其芯径比平方的2.4倍,这对构建全光纤转动喇曼激光雷达系统具有重要意义.     

集成光学条波导阵列与单模光纤阵列的联接

本文报告了一种新的集成光学条波导阵列与镶嵌在硅V槽中的单模光纤阵列耦合联接方法的设计考虑,导出了确定光纤正确位置及V型槽的几何尺寸的若干计算公式.并讨论了光纤与波导几何尺寸与耦合效率的关系.指出了这是实现单模光纤阵列与条波导阵列的固定联接的有效方法,它简化了波导与光纤的对准程序,即由五维调整简化为平面的一维调整.可实现多个波导和多个光纤的同时对准与固定.最大限度地利用了有效重叠面积,从而提高了光纤与条波导的耦合效率.一组典型的数据是单模光纤(芯径10μm)对单模波导(10μm×5μm)的耦合效率可达55%,而同样尺寸的波导对光纤的最大耦会效率可达86%.     

基于ABCD矩阵的楔形柱面光纤微透镜的耦合技术分析

运用激光模式耦合理论分析了半导体激光器与楔形柱面光纤微透镜的连接损耗,设计并制作了楔形柱面光纤微透镜用来实现两者的模斑匹配。运用ABCD矩阵方法,对该组件的耦合效率进行了仿真计算和分析,得到了高耦合效率下楔形柱面光纤微透镜的结构参数。该方法可有效地用于楔形柱面光纤微透镜的优化设计。     

半导体激光器与单模光纤耦合效率的分析

在高斯场分布近似的前提下,从模场半宽匹配的角度描述了半导体激光器（ＳＬＤ） 与单模光纤（ＳＭＦ） 之间的光耦合理论。对不同的ＳＬＤ ＳＭＦ 间光耦合的方式作了分析,并从耦合效率与成本双重角度给出了适合于实际工程应用的几种耦合方式的优选率     

Tapered microstructured fibers for efficient coupling to optical waveguides: a numerical study

We report the possibility of using tapered microstructured fibers to improve the coupling efficiency from a standard single-mode fiber to a photonic crystal waveguide. The tapered microstructured fiber allows for the reduction of the mode mismatch between the output of the standard fiber and the input of the waveguide while maintaining single-mode guidance, which results in an enhanced coupling efficiency. Numerical simulations are conducted in order to optimize the cross section of the microstructured fiber as well as the taper profile. An improvement of more than 4 dB is obtained compared to non-tapered fibers. For further improvement, an elliptical-core tapered microstructured fiber is analyzed. The effect of misalignment between the tapered microstructured fiber and the waveguide is also studied.     

Coupling methods in prospective single-mode fiber integrated optics systems: A progress report

A review of the research progress on the coupling of fibers to fibers, fibers to thin-film waveguides, and thin-film waveguides to thin-film waveguides is presented here. In general, the direct excitation method is preferred for the coupling of two fibers, with efficiency larger than 90%. The direct excitation method is also preferred for the coupling of two thin-film waveguides and thin-film waveguides to fibers where the two component waveguides have vastly different refractive indices. The coupling efficiency depends on matching the field pattern of component waveguides. The laser source to fiber launching is done mostly by direct excitation. The evanescent field coupling method is preferred for the coupling of two thin-film waveguides that have close refractive index profiles, with efficiency larger than 70%.     

Passive T-bus with asymmetrical 4-port couplers

A newly designed 4-port coupler in planar technology is described. The axes of the coupling fibers are mutually offset as before, but the input fiber is thinner than the other three, and its diameter is matched to the emitting surface area of the light source serving as a transmitter. Low insertion loss and high coupling efficiency are realized through the choice of favorable dimensions. Graphs show the output coupling efficiency, input coupling loss, and insertion loss with step-index fibers as a function of the axial offset. The maximum number of terminals that can be connected to the T-bus is calculated for various conditions. The number of terminals is found to be about 40% higher than is possible with the coupler with four identical fibers.     

Passive T-bus with asymmetrical 4-port couplers

Abstract

A newly designed 4-port coupler in planar technology is described. The axes of the coupling fibers are mutually offset as before, but the input fiber is thinner than the other three, and its diameter is matched to the emitting surface area of the light source serving as a transmitter. Low insertion loss and high coupling efficiency are realized through the choice of favorable dimensions. Graphs show the output coupling efficiency, input coupling loss, and insertion loss with step-index fibers as a function of the axial offset. The maximum number of terminals that can be connected to the T-bus is calculated for various conditions. The number of terminals is found to be about 40% higher than is possible with the coupler with four identical fibers.     

单模光纤与Ti:LiNbO3单模平面光波导端面激励耦合的研究

本文报导一个单模光纤与单模Ti扩散LiNbO3光波导的端面耦合及固定连接实验研究.利用电弧烧熔法在单模光纤端面上制成了微透镜,改善了模场匹配程度,采用二维硅V形糟,提高了光纤与波导的对准精度。     

Fused angle-polished multi-points side-pumping coupler for monolithic fiber lasers and amplifiers

We have developed theoretical model to investigate characters of fused angle-polished side-pumping coupler for monolithic fiber lasers and amplifiers. In the simulation the interplay of different couplers is considered. Five pumping fibers with different polished angles are employed in the experiment. The results showed that, the backward coupling efficiency, forward and backward pumping leakage are lower than 4%, 8% and 10% respectively, while the forward coupling efficiency is about 100%, with the polished angle suitable for commercial fibers. The experimental results agree well with the simulations. Furthermore, we fabricate a two-points co-propagating fused angle-polished side-pumping coupler, with the coupling efficiency of 94.1% and 87.9%. These couplers are quite suitable for multi-points side-pumping high power monolithic fiber lasers and amplifiers.