共查询到20条相似文献,搜索用时 31 毫秒
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Jaeheung Kim Choon Sik Cho Barnes F.S. 《Microwave and Wireless Components Letters, IEEE》2005,15(5):348-350
A new form of a Rotman lens has been proposed for applications above 10 GHz, such as a collision avoidance radar. The proposed lens can be described as a dielectric slab fed by slot lines. The new form is expected to show lower loss and lower mutual coupling than the conventional Rotman lenses at higher frequency than 10 GHz. The prototype was implemented with nine beam ports and nine array ports. The measurements show that the mutual coupling can be lowered at higher frequency, and that the efficiency of the dielectric slab lens of about 30% can be obtained. We conclude that the dielectric lens is comparable to the conducting plate lens even though a spillover loss is presumed at frequency of the implementation. 相似文献
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《Microwave Theory and Techniques》2005,53(8):2622-2627
A new form of a Rotman lens is proposed for microwave/millimeter-wave applications such as a collision-avoidance radar. The proposed lens can be described as a dielectric slab fed by slot lines. The new form is expected to show lower loss and lower mutual coupling than the conventional Rotman lenses fabricated with conducting plates at millimeter-wave frequency. Taking the field distribution inside the dielectric slab into account, the$ TE_0$ mode was chosen to excite the dielectric slab lens. The dielectric Rotman lens consists of a dielectric slab, tapered slot structure, and the transitions between the antipodal slots and microstrip lines for subminiature A connectors. The conventional design equations have been modified for use in designing the dielectric slab Rotman lens with a high dielectric material. A prototype was implemented with nine beam ports and nine array ports. Measurements from 10 to 20 GHz show that mutual coupling can be lowered at higher frequency. The obtained efficiency of the dielectric slab lens system is approximately 30%. The efficiency of the lens is comparable to that of the conducting plate lenses even though there is a spillover loss from the dielectric slab. 相似文献
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A compact nonreciprocal optical circuit for laser-diode-to single-mode-fibre coupling using a YIG sphere is proposed in the 1.3 ?m wavelength region. It is clarified that the YIG sphere can function as an effective Faraday rotator as well as a coupling lens. A high isolation value of more than 30 dB has been realised with coupling efficiency of ?5.2 dB for a single-mode fibre. 相似文献
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Suzuki A. Wakazono Y. Suzuki S. Tamura M. Masuda H. Ishikawa T. Hashimoto Y. Suzuki T. Kikuchi K. Nakagawa H. Aoyagi M. Mikawa T. 《Electronics letters》2008,44(12):724-725
High optical coupling efficiency of more than 80% between an optical fibre and a vertical-cavity surface-emitting laser (VCSEL) has been achieved without use of a lens. A 45deg-ended fine-drawn optical fibre can be positioned closer to a VCSEL than a conventional multimode fibre. 12.5 Gbit/s/ch optical signal transmissions using a low-height optical coupling structure have been demonstrated with optical output power as high as +2.0 dBm without use of a lens. 相似文献
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A theory for the calculation of the spherical aberration loss of silicon planoconvex lenses is presented. The aberration losses are calculated as a function of the lens parameters. Furthermore, a theory for the coupling efficiency of a laser diode to single-mode fiber for a coupling arrangement consisting of a silicon planoconvex lens and a glass ball lens is given. The theoretical predictions are in good agreement with measurements. Experimentally, a coupling efficiency of 72% (1.4-dB coupling loss) was achieved for a laser diode with farfield angles of 20°×33° FWHM and a not yet fully optimized silicon planoconvex lens 相似文献
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Reith L.A. Mann J.W. Lalk G.R. Krchnavek R.R. Andreadakis N.C. Zah C. 《Lightwave Technology, Journal of》1991,9(4):477-484
The authors present an approach to single-mode fiber coupling which results in relaxed alignment tolerances during the package assembly process. The authors use a ball lens to couple from the optical device either directly to single-mode fiber (SMF), or indirectly to SMF through a fiber lens. The ball lens is aligned and mounted in the first assembly stage. The lens is aligned and fixed either mechanically or semiactively. In the second stage of assembly, the SMF is aligned so as to compensate for any small misalignments of the ball lens. The authors have achieved coupling efficiencies of 33-40 % with this coupling scheme. It has been used for coupling to standard laser diodes and to near-traveling wave optical amplifiers. Fiber-to-fiber gains of 8.5-10 dB have been achieved with packaged devices. The approach provides some versatility with respect to the placement of passive optical components inside the package 相似文献
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The best compromise between coupling efficiency, accuracy of positioning and reproducibility has been obtained for a high index hemispherical lens melted on the tip of an intermediate fibre between the GaAlAs laser and the transmission fibre. The letter describes the lens fabrication technique and gives various experimental results of coupling efficiencies and mechanical tolerances. 相似文献
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自聚焦透镜用于端泵浦DPL的耦合光学系统 总被引:1,自引:0,他引:1
本文用自聚焦透镜耦合LD输出,解决了需要短焦距、大数值孔径透镜的设计和制方面的困难。提出了计算自聚焦透镜耦合效率的简化模型。用自聚焦透镜和一对正交柱面透镜设计了一个耦合系统,并用该耦合系统端泵浦Nd:YAG棒做了实验。 相似文献
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具有去包层球锥透镜的多模光学纤维与条形DHGaAlAs激光器之间的耦合 总被引:1,自引:0,他引:1
本文报导了采用去包层球锥透镜实现光纤维与条形DH GaAlAs激光器之间高效率的耦合。从理论上分析了这种高效率耦合机理,并设计了这种透镜。实验上获得了90%的耦合效率。实验也表明包层球锥透镜的耦合效率为最高,与理论分析相一致。 相似文献
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A new efficient coupling circuit, using a combination of a cylindrical lens and a Selfoc lens, which can be mounted in a laser package, has attained a coupling loss nearly as low as 0·6 dB. 相似文献
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Theoretical coupling efficiency between a channel waveguide and a single-mode optical fibre using a ball lens is optimized by varying the parameters of the optical system such as the relative position of the components, the refractive index and the size of the lens. A specific software has been used for the optimization. Numerical calculations have been done under the Gaussian approximation of the fields distributions. The losses due to waveguides misalignments with respect to their ideal position have been evaluated. All these theoretical results are compared with those obtained from buttcoupling. 相似文献
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A design method for a miniature optical lens tipped on a single-mode fiber end to improve power coupling from a semiconductor laser is described. The lens shapes studied are hemispherical, hemicylindrical, and hemiellipsoidal. The optimum coupling conditions and the obtained coupling efficiency are represented in terms of laser beam and fiber parameters. Preferable ranges of hemispherical and hemicylindrical lenses are classified according to the laser and fiber mode spot sizes. Fiber axis offset and tilt effects on coupling efficiency are also studied. 相似文献
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An optical isolator for laser-to-single-mode fiber coupling is discussed. The coupling unit consists of a confocal two-lens system with a spherical glass lens and a planoconvex lens which is made of yttrium iron garnet (YIG). To minimize the number of elements, the YIG lens is used as a Faraday rotator as well as a coupling lens. Nevertheless, the planoconvex YIG lens satisfies the requirements of high coupling efficiency, high isolation, and low optical feedback from the Faraday rotator. The arrangement is theoretically and experimentally investigated. At a coupling efficiency of 34%, the total optical feedback into the laser diode was measured to be about -60 dB 相似文献
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基于偏振复用技术的激光二极管光纤耦合方法 总被引:2,自引:0,他引:2
光纤耦合输出的高功率激光二极管(LD)模块作为光纤激光器的抽运源已经得到了广泛应用。为了进一步提高光纤耦合激光二极管输出功率,提出了利用激光二极管输出光束的线偏振特性,采用偏振复用技术,将两只高功率激光二极管输出光束经准直、复合、聚焦的光纤耦合方法。利用光线追迹法,分析了圆柱透镜对激光二极管发散光束的准直特性,并讨论了柱透镜的安装距离对准直性能的影响。根据激光二极管和光纤的相关参数设计了聚焦透镜组。采用这种方法将两只输出波长为980 nm的高功率激光二极管输出光束耦合进数值孔径0.22,芯径100μm的多模光纤中,当工作电流为4.5 A时,光纤激光连续输出功率为6.36 W,耦合效率大于78%。 相似文献
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基于热扩芯光纤的光纤准直器特性研究 总被引:1,自引:0,他引:1
为了提高光纤和光器件之间的耦合效率,设计了由热扩芯光纤和自聚焦透镜构成的新型热扩芯光纤准直器。理论上分析了热扩芯光纤准直器的基本结构参数与光学特性的关系以及由3种失配导致的耦合插入损耗。研究发现,热扩芯光纤准直器的耦合特性与自聚焦透镜的参数有关,热扩芯光纤准直器在轴向间距和角度偏差上的耦合失配容限明显优于普通光纤准直器,横向位移损耗则高于普通光纤准直器。采用模场半径为15.4μm的热扩芯光纤与自聚焦常数为0.295mm-1的自聚焦透镜制备了热扩芯光纤准直器,并对热扩芯光纤准直器因3种失配导致的耦合插入损耗进行了理论和实验比较,结果表明实验数据与理论吻合较好,说明所设计的热扩芯光纤准直器可用于长距离光耦合和旋转连接器件。 相似文献
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A new method for coupling single-mode fibre to laser diodes employing a spherical ruby lens and a single-mode optical fibre up-taper is demonstrated. High coupling efficiency and greatly reduced alignment sensitivities are attained 相似文献
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Murakami Yasuji Yamada Jun-ichi Sakai Jun-ichi Kimura Tatsuya 《Electronics letters》1980,16(9):321-322
A new fabrication method for a hemispherical microlens on optical fibre ends is proposed, to achieve high coupling efficiency between an InGaAsP laser with a buried heterostructure geometry and a single-mode fibre. The microlens is fabricated by attaching silica glass to the fibre end, which is then heated to form the desired shape by electric discharge. The lowest coupling loss of 2.9 dB has been achieved by selecting the optimum lens radius at 8.5 ?m. Effects of misalignment are also reported. 相似文献
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A practical laser diode module is demonstrated for single-mode fiber applications. The module was developed through the use of a new combination lens method. The second lens in the confocal two-lens method is divided into two lenses. One is attached to the single-mode fiber front endface, thus forming a virtual fiber. Since both virtual fiber and lens misalignment tolerances are large in this coupling method, soldering is easily applicable. The laser diode module could be fabricated as easily as that for a multimode fiber. High coupling efficiency, excellent reproducibility, and high reliability were confirmed in trial-fabricated modules. Moreover, output power fluctuation due to reflected lightwaves was found to be very small. 相似文献