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。     

激光用的单模光纤终端微透镜

制作在光纤终端的微透镜最早是用来改的应用也都在进行研究，包括功率传输、内窥进光源和光纤的耦合。由于低耗光纤价格下镜、光纤传感、流量测量等等,然而,还未闻有降,其应用不断增多,除光纤通讯外许多方面人在光纤终端制作微透镜用于激光记录和激光扫描系统。     

新型共焦组合透镜法的单模光纤激光二极管组件

针对单模光纤的应用,我们研制了一种实用的激光二极管组件。该组件已在组合透镜法中得到应用。其作法是把两透镜共焦法中的第二透镜分成两个透镜,将其中之一紧贴到单模光纤的前端面,形成一根准光纤。该耦合法中准光纤和透镜两者的偏移容限都很大,因此易于焊接。这样,单模光纤激光二极管组件的制造就可能像多模光纤组件一样容易。组件的制造证实了这种方法耦合效率高、重复性好及稳定性高,而且,还发现因反射光引起的输出功率的波动也很小。     

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%.     

激光二极管与单模保偏光纤的耦合分析

给出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,讨论了透镜参数、耦合形式、激光二极管像散对耦合效率的影响,给出两种实际耦合系统的计算结果并与实验结果作了比较     

用微型全息透镜作单模光纤的最佳耦合

提出微型全息透镜（MHLs）可作为光网络系统中半导体激光器与光纤、波导等之间的外耦合器，合理设计制作的MHLs能代替一个复杂的光学系统进行耦合，初步的光纤耦合实验得到其耦合效率比直接耦合提高了1倍多。并且提出MHLs还可与垂直腔表面发射激光器（VCSEL）组合成自准直集成系统。文中给出了理论分析、实验方法、实验结果和进一步的改进建议。     

面向SOI波导-单模光纤耦合的硅微透镜设计

硅光集成的优势在高速光电子领域不断凸显,被广泛应用于各种通信场景中。在硅基集成技术发展过程中,其面临的一个典型技术难点是硅波导与单模光纤的耦合。本文设计了波导边缘集成的硅微透镜结构,经BPM法(Beam Propagation Method)计算验证该结构可实现3μm厚SOI波导与纤芯直径86μm单模光纤90的近场耦合效率,具备高集成度、高耦合效率、多场景适用等优点。     

光纤端面球透镜耦合设计

选取s/r,是光纤端面球透镜耦合设计的关键。本文主要讨论求最佳的光纤球面状端面曲率半径roptim和光纤端面到光源距离soptim的一种较为简便的方法。由于采用y/r作变数就可以给出(y/r)_(γmin)的解析表达式,所以可以把参数(s/f)_(optim)的确定做得很精确。     

端面球透镜光纤与激光器的耦合

一、前言激光器与光纤的耦合在光通信系统中占有比较重要的地位。如何提高耦合效率以及改进耦合器的结构性能是最近几年中耦合器研制方面的主要课题之一。对此,国内外都进行了许多研究,取得了很大的进展。特别是激光器与光纤的耦合,在耦合方式上有端面球透镜、锥状透镜、柱透镜、自聚焦透镜,以及这些透镜     

用于半导体激光器到单模光纤耦合的圆锥端微透镜设计

介绍了一种用于半导体激光器-单模光纤耦合的圆锥端半球透镜的耦合效率的理论计算.失配不存在时,耦合效率随着锥长的增加而减小.失配存在时耦合效率随轴向和角向失配的增大而减小.     

Ideal microlenses for laser to fiber coupling

The design and fabrication of ideal microlenses for semiconductor laser to fiber coupling are reported. Properly coated for reflections, lenses of the new design can theoretically collect 100% of the radiated energy of a modal-symmetric laser source. The crucial feature is its hyperbolic shape. Microlenses fabricated directly on the end of the fiber by laser micromachining have demonstrated up to 90% coupling efficiency. This performance represents a major advance in microlens technology when compared to currently fabricated hemispherical microlenses which are at best 55% efficient. A theoretical comparison of the two lens shapes illuminates the advantages of the hyperbolic profile. The ability to couple all of the light from a semiconductor laser into a fiber has far-reaching implications for all optical communication systems     

Characteristics of a hemispherical microlens for coupling between a semiconductor laser and single-mode fiber

A hemispherical microlens is fabricated on the end of a single-mode fiber by an electric arc discharge technique. It improves coupling efficiency between InGaAsP lasers with buried heterostructure geometry and single-mode fiber. The lowest coupling loss of 2.9 dB is achieved with the optimum lens radius of 8.5 μm. This loss is 4.4 dB lower than that with a butt joint. Experimental results of coupling efficiency and alignment tolerances in coupling with different lens radii in the range of3.5-17 mum are discussed in detail. The results are in good agreement with theoretical values derived by Gaussian beam and paraxial ray approximations.     

Efficient self-aligning multibeam coupling into a single-mode fiber

We present and demonstrate a method for efficient coupling of many beams into a single-mode fiber. Using the phase conjugating property for mutually incoherent beams of the double phase conjugate mirror (DPCM), we achieved coupling for a full 6×6 matrix of beams into a single-mode fiber. In principle, this number of input channels can be increased manyfold beyond the 36 used in our experiment. Of the phase conjugate generated by the DPCM in the direction of the fiber, over 97% (Fresnel corrected) entered the fiber, thus giving a highly accurate coupling. The DPCM transmission efficiency itself was measured at 40% (Fresnel corrected), thus giving an overall coupling efficiency of 39%. By optimizing the DPCM parameters, a significantly higher overall coupling could be achieved. An additional advantage of this method is that the DPCM will reconfigure if there are small changes in the system, thus making the system very robust. This multichannel coupling method can be of importance in the coupling of the output beams of a vertical cavity surface emitting laser (VCSEL) into a single-mode fiber where each channel may carry independently modulated information. This technique can be further generalized to a bidirectional multisingle-mode fiber interconnection system, of which a basic 3×2 system is demonstrated     

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.     

Asymmetric fiber microlenses for efficient coupling to ellipticallaser beams

It is demonstrated that it is possible to fabricate asymmetric hyperbolic microlenses directly on the ends of single-mode optical fiber to enhance the fiber's coupling to elliptical laser beams. The lenses, with controlled eccentricity ratios, are made by micromachining the end of the fiber with a pulsed CO₂ laser, as the fiber is directed by computer control about the focussed laser beam. Coupling efficiencies of 84% (-0.74 dB) have been realized with single transverse mode lasers at a wavelength of 0.98 μm having an approximately 3 to 1 beam ellipticity. With multitransverse-mode lasers at 1.48 μm having similar ellipticities, the asymmetric lenses demonstrate a 2-dB increase in coupling efficiency over symmetric hyperbolic microlenses. The authors have coupled about 120 mW from such a 360 mW laser, used to pump erbium-doped fiber amplifiers, into single-mode fiber     

光纤偏移对空间光-单模光纤耦合效率的影响

空间光-单模光纤耦合的关键技术是怎样确保耦合系统中光纤的准确定位。基于电磁场模场匹配理论,讨论了光纤偏移对空间光-单模光纤耦合效率的影响,结果显示耦合效率随着光纤偏移的增大显著下降。采用光纤调整架以及微透镜光纤可以显著改善耦合效率,讨论结果有助于空间光-单模光纤耦合器件的优化设计。     

Direct coupling from a GaAs laser into a single-mode fibre

Ways of coupling directly to a monomode fibre by neutralising the end reflection from the laser and then using the face of the fibre core as a cavity mirror are proposed. The condition is derived for the optimum transfer of power from the laser resonator to the fibre transmission line.     

激光成像系统中高耦合效率单模光纤耦合器设计

在三维激光成像系统中,其性能表现绝大部分决定于器件接收背反射光能幅度的大小,以及耦合器中空间光到光纤纤芯的光耦合效率的高低.为了增加耦合器中激光能量到纤芯内的耦合效率,提出了一种新型非球面透镜到锥形光纤头的耦合器的设计,得到了该耦合器中耦合效率的解析表达式.通过优化耦合透镜的倒相对孔径,对应波长为1 310 nm和1 ...     

Tapered single-mode optical fiber evanescent coupling

We describe the results of a numerical and experimental investigation of how a point source of radiation couples light to the HE ₁₁ mode of a tapered single-mode fiber. Specifically, we have investigated two different geometries of nonadiabatic, tapered single-mode optical fiber. The motivation for this study is the characterization of a single-mode tapered optical fiber biosensor. In such a device light is collected from fluorescent sources located along the cladding surface of the tapered fiber. Taper-to-taper coupling measurements and fiber mode calculations indicate the device sensitivity decreases exponentially as sources are moved away from the tip of the tapered fiber     

Light coupling from a semiconductor laser into a polarisation-maintaining single-mode fibre

For laser to polarisation-maintaining fibre coupling we propose the insertion of a short piece of normal single-mode fibre. As a result a power coupling loss of 2.8 dB is obtained, whereas additional crosspolarisation is very small compared with the unwanted polarisation excitation of the laser itself.