半导体增益芯片与微透镜光纤耦合效率研究

光纤光栅外腔半导体激光器一般采用波导-光纤的直接耦合方式,光纤与增益芯片的耦合效率对光纤光栅外腔半导体激光器性能影响较大.为了讨论在采用不同类型光纤微透镜时对准误差对耦合效率的影响,寻找最佳微透镜类型,指导器件的设计和装配,分析了锥形和半球形光纤透镜的光线最大接收半角,利用ZEMAX软件进行模拟仿真,得到了两种光纤微透镜分别在位置误差和角度误差下的耦合效率曲线图.结果表明,锥形光纤透镜耦合效果更好,更适合应用于光纤光栅外腔半导体激光器.     

锥形微透镜保偏光纤与超辐射发光二极管的耦合

对采用锥形光纤微透镜的保偏光纤与超辐射发光二极管的耦合进行了理论分析.制作出几种不同的微透镜保偏光纤,并对它们进行了耦合试验,找到了制作具有高耦合效率的微透镜保偏光纤的方法.     

微透镜光纤在半导体激光器中的应用研究

对几种典型的半导体激光器与光纤的耦合特性进行分析,提出提高耦合效率所采用的微透镜光纤的结构.介绍熔拉型、化学蚀刻型、研磨抛光型、切削型、自聚焦光纤型和铸模型等微透镜光纤的制作原理和工艺以及目前达到的指标,并对各种形式的透镜光纤进行了评价.提出了提高耦合效率和失调容差、降低插损的新思路.     

974nm半导体激光器的光纤耦合研究

根据半导体激光器和单模光纤模场分布特点,用模式耦合理论研究了单模光纤与半导体激光器的耦合,结果表明将光纤端面制作成楔形微透镜可以使光纤与半导体激光器的耦合满足模场匹配和相位匹配的要求。用遗传算法对楔形光纤微透镜参数进行优化,得到楔角为88°,柱透镜半径为3.44μm,耦合距离为6.13μm时耦合效率达到最佳值,用Zemax光学仿真软件对耦合模型进行仿真,得到耦合效率为88.9%,耦合好的模块经激光点焊及高低温环境测试后,得到最大耦合效率为81.36%。实验结果与仿真结果相差不大,耦合输出功率满足了作为光纤激光器种子源的功率要求。     

激光二极管与单模保偏光纤的耦合研究

给出了一种处理激光二极管经透镜与单模保偏光纤耦合的精确方法,测量了半导体激光器的光束质量,对其光束的收集、准直、整形、聚焦和耦合进入光纤进行了实验研究,同时测量了整形系统和光纤的定位灵敏度.对球面微透镜光纤与激光二极管耦合的方法进行了理论分析,讨论了透镜参数、耦合形式、激光二极管波像散对耦合效率和特性的影响,给出了2种实际耦合系统的实验计算结果,并与理论计算作了比较,结合实验得到了微透镜的优化参数,且将结果应用到了激光二极管与单模保偏光纤耦合实验中,得到了总的耦合效率为36%.     

与光纤阵列耦合的微透镜阵列设计与损耗分析

设计了2种不同冠高的圆形微透镜阵列,将平行光耦合进16路单模光纤阵列和多模光纤阵列。每种微透镜阵列均由16个直径为120pm的平凸微透镜排成一行组成,相邻微透镜间距为127μm。模拟其成像特性知,2种微透镜可以将平行光会聚成在其像平面直径分别为8．0μm和32．5μm的光斑。分析了微透镜与光纤存在横向、纵向和角向误差3种位置失配时的耦合损耗,并得出对耦合损耗影响最大的因素是角向误差,由此得出：在微透镜与光纤耦合对准过程中,要注意减小角向误差。     

基于微透镜阵外腔的光纤激光谱组束耦合效率分析

为了克服光纤激光外腔谱组束系统中增益带宽和透镜像差对组束阵元数量的限制,在系统中加入了微透镜阵。根据光束变换理论,建立了基于微透镜阵的光纤激光外腔谱组束系统的外腔耦合效率分析模型。通过数值模拟,对各种相关参数对耦合效率的影响进行了仿真分析。结果表明:微透镜阵的加入极大提高了阵元的耦合效率和系统的组束潜力;为了获得尽可能高的耦合效率,需要对离焦量进行合理配置并设计具有较长焦距的微透镜;横向对准误差是影响耦合效率的主要因素,对于宽度为10 mm的组束光纤阵列,为保证60%以上的耦合效率,在θy≤2 mrad的同时需将横向位置偏移量δy限制在10μm以内。     

高功率半导体激光器列阵光纤耦合模块

根据大功率半导体激光二极管列阵与光纤列阵耦合方式, 分别从理论和实验两方面讨论、分析了大功率半导体激光二极管列阵与微球透镜光纤列阵耦合。将19 根芯径均为200 μm 的光纤的端面分别熔融拉锥成具有相同直径的微球透镜, 利用V 形槽精密排列, 排列周期等于激光二极管列阵各发光单元的周期。将微球透镜光纤列阵直接对准半导体激光二极管列阵的19 个发光单元, 精密调节两者之间的距离, 使耦合输出功率达到最大。半导体激光二极管列阵与微球透镜光纤列阵直接耦合后, 不仅从各个方向同时压缩了激光束的发散角, 有效地实现了对激光束的整形、压缩, 而且实现30 W 的高输出功率, 最大耦合效率大于80%, 光纤的数值孔径为0.16。     

基于微透镜阵列的高效率光纤耦合系统设计

光纤耦合是半导体激光器集成光源进一步改善输出光束质量和远距离传输的重要手段。然而,由于半导体激光器单管体积和散热的限制,合成后激光光源的输出光束光参量积仍较大,不利于与单根多模光纤的耦合;直接与光纤束耦合又受到光纤束填充比的限制。针对多个半导体激光器单管集成的光源,采用倒置前端光学放大系统,对合成光束直径进行压缩;并采用六方排列的微透镜阵列作为耦合元件,使其光瞳成像在光纤端面,从而实现微透镜与光纤的一对一耦合,得到理论无损耗的高效光纤耦合系统。为了改善光场边缘像差影响,采用空心光管进一步匀化光场分布,且减小了边缘光线的发散角,提高了边缘光线的成像质量,优化后的系统耦合效率达98%。这一系统利用微透镜阵列将光束分束、成像,克服了集成光源输出光束光参量积较大不易与单根光纤耦合的缺点;通过使微透镜的入瞳成像在光纤端面,且光纤束的排列与微透镜阵列排列相同,提高了光束与光纤束的耦合效率。     

GRIN光纤传输特性及其在透镜光纤耦合系统中的应用研究

论述了GRIN光纤传输特性与自聚焦原理,分析了LD与光纤的耦合特性,介绍了微透镜光纤的结构、高效耦合原理与加工工艺以及技术指标.提出采用GRIN与普通光纤级联,进一步提高耦合效率和失调容差的新思路.     

激光器与单模光纤球透镜耦合的蒙特卡洛分析

为了研究半导体激光器与单模光纤在采用球透镜耦合方式的封装过程中不同耦合参量对耦合效率的影响,建立了半导体激光器与单模光纤通过球透镜耦合的光传输模型。基于ABCD矩阵和高斯光束与单模光纤耦合理论,计算了半导体激光器与单模光纤的球透镜耦合效率,以光功率下降0.5dB为评判标准,给出了在透镜半径为0.5mm时的各参量容忍度。采用蒙特卡洛分析方法,结合耦合效率计算模型,模拟仿真了各参量满足正态分布时的耦合效率分布状况。结果表明,能达到的最大耦合效率为0.616,最大概率耦合效率为0.585,参量区间缩小一半对耦合效率的提升较明显,但进一步缩小参量区间对耦合效率的提升不明显。此研究方法对激光器件封装过程中的对准单元精度选取与耦合效率预估具有指导意义。     

High-efficiency two lens laser diode to single-mode fiber couplerwith a silicon plano convex lens

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     

An optimum approach for fabrication of tapered hemispherical-end fiber for laser module packaging

Comprehensive measurements of the dependence of coupling efficiency and radius of curvature on taper angle in a tapered hemispherical-end fiber (THEF) for coupling between laser diodes and single-mode fibers are presented. The THEF was fabricated by etching the fiber end in a hydrofloride (HF) solution with a thin layer of oil floating on top of the HF, and then heating in a fusion splicer to form a hemispherical end. The results show that THEFs with larger taper angles fabricated by greater oil density exhibit a smaller radius of curvature, and hence a better coupling efficiency. The results of this investigation have led to an optimum approach for high-yield and high-volume fabrication of THEFs that is suitable for use in commercial laser diode modules for efficient coupling between laser diodes and single-mode fibers. The calculation of the effect of oil density in HF etching solution on taper angle based on a semiempirical model is in good agreement with the measured results.     

高功率光纤放大器中光纤端面处理分析

光纤端而进行斜而抛光一直是高功率光纤放大器中抑制ASE和自激振荡的关键技术.根据放大器结构建立了光纤端面信号光注入、信号激光输出以及泵浦光耦合的物理模型,数值模拟了不同光纤斜端面角度下信号光、泵浦光的耦合效率,纤芯端而的回波损耗.结果表明信号光注入端而斜面处理会导致耦合效率降低,输出端面斜角处理可有效减小端面反射率,而微小斜角对泵浦激光进入光纤内包层的耦合效率影响不大;根据不同的光纤参数选择合理的斜角处理可以有效提高放大器性能.     

Arrayed Multimode Fiber to VCSEL Coupling for Short Reach Communications Using Hybrid Polymer-Fiber Lens

We report the novel method that can give high coupling efficiency between a vertical-cavity surface-emitting laser (VCSEL) array and a multimode optical fiber ribbon by using a hybrid-polymer-fiber lens technique. The coupling efficiency as high as 91% was achieved by optimizing the polymer lens curvature for the single source to the single fiber case. The longitudinal and the transverse coupling tolerances were enhanced with the introduction of a coreless silica fiber (CSF) segment between the fiber and the lens tip. The tradeoff between the high coupling efficiency and the large tolerance was experimentally observed. The technique was further applied to the coupling between a four-channel VCSEL array and a four-core fiber ribbon for short reach applications. The procedure of fabrication and the analysis of their optical characteristics are reported.     

大功率半导体激光器光纤耦合模块的耦合光学系统

针对 8 0 8nm大功率 Ga As/ Ga Al As半导体量子阱激光器的远场光场分布特点 ,提出了与多模光纤耦合时对耦合光学系统的特殊要求 ,并根据低成本、实用化的要求设计制作了专用的耦合光学系统 ,对耦合光学系统的实际性能进行了测试 ,给出了耦合效率统计分布图、耦合偏差曲线和高低温可靠性实验结果 .用设计制作出的实用化耦合光学系统完成了输出功率 15— 30 W,光纤束数值孔径为 0 .11— 0 .2 2的半导体激光光纤耦合模块 ,模块的使用结果表明耦合光学系统稳定、高效、实用     

Spot size expansion for laser-to-fiber coupling using an integratedmultimode coupler

Efficient coupling of light from a semiconductor waveguide to an optical fiber is difficult to achieve due to the inherent differences in the spot sizes. The problem is particularly severe in the vertical dimension. The use of a uniform, untapered, intermediate coupler structure which consists of a multimode waveguide is proposed. This structure has potential for integrating with the semiconductor waveguide. The basic design rules for this coupler are worked out using coupled-mode theory, and the detailed designs are based on direct calculation of the mode profiles in the coupler. A range of realistic examples is examined, and it is shown that the butt coupling efficiency from a typical semiconductor laser to an optical fiber can be improved by up to 5 dB. The dependence of performance on fabrication tolerances is also studied     

空间散射光到单模光纤的耦合

空间散射光到光纤的耦合在许多领域都得到广泛的应用。然而,当被测物体较大时,如何有效地将空间散射光有效地耦合到光纤的研究还较少。耦合效率和接收视场是空间散射光耦合到光纤接收装置的两个重要的特性参数。文中通过理论分析和软件仿真,分析了在径向移动、轴线移动和不同入射角的情况下,改写耦合效率的变换,比较了在满足一定的耦合效率时,光纤接收装置的几种透镜耦合方式接收视场的大小。最后,通过实验对仿真内容进行了验证。     

Optical Coupling Methods for Cost-Effective Polymer Optical Fiber Communication

In this paper, we report cost-effective light coupling methods for polymer optical fiber (POF) communication. Here, we compare the various optical coupling schemes in detail. By optical simulations, we analyze the conventional light coupling schemes, namely the direct coupling, lens coupling, and lensed fiber coupling. The simulation studies reveal that a lensed fiber tip particularly at the receiver side improves the light coupling efficiency to a great extent. The optimized lensed POF design confers an 85% coupling efficiency. Lensed POFs are realized with two low-cost fabrication methods. The characterization of the lensed POF are carried out to evaluate the lensing properties and hence to optimize the fabrication process.     

Design of a miniature lens for semiconductor laser to single-mode fiber coupling

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.