基于温度激励的光纤陀螺光纤环瞬态特性检测

光纤陀螺基于萨尼亚克效应测量垂直于光纤环平面的敏感轴方向上的旋转分量。光纤环是光纤陀螺的核心部件,光纤环的缠绕质量直接影响着光纤陀螺的整体性能,对光纤环的缠绕质量全面检测十分必要。针对目前光纤环检测手段的局限性,提出了一种基于温度激励的光纤陀螺光纤环瞬态特性检测方法,全面表征了光纤环的缠绕质量。建立了光纤环柱面坐标三维计算模型,采用有限元方法定量分析光纤环不对称度和局部温度激励位置精度对光纤环瞬态响应的影响,同时开展了光纤环温度激励相应实验,实验结果与光纤环三维物理模型数值计算结果相一致,在理论和实验上验证了光纤环瞬态特性检测方法的可行性。     

光纤弯曲对干涉式光纤陀螺性能的影响

为研究光纤弯曲对干涉式光纤陀螺性能的影响,选取常用的单模光纤、保偏光纤、光子晶体光纤及保偏光子晶体光纤为研究对象,建立了光纤弯曲与光纤陀螺性能的相关理论模型。以高精度光纤陀螺应用为背景,选取掺铒超荧光光纤光源,改变光纤弯曲半径,测出了经过光纤样品后的光功率、平均波长、光谱宽度的变化和平均波长波动,在此基础上分析了弯曲半径对光纤陀螺标度因数和随机游走系数的影响。理论分析和实验结果表明,采用光子晶体光纤时,光纤弯曲对光纤陀螺性能几乎没有影响,采用其他光纤时,需要严格控制光路中的光纤弯曲半径。     

光纤激光器用光纤研究现状及展望

对于光纤激光器,其光输出光束性能的好坏与反馈回路中的光纤的质量有直接关系。就光纤激光器用光纤做出阐述,综述了光纤的基础知识,介绍了稀土掺杂光纤、光纤激光器与放大器平台,最后对新兴的光纤技术以及未来发展趋势做出展望和结论。     

光纤传感器系统中的功能光纤

本文结合光纤传感器的应用实例,对光纤传感器中光纤的选用进行了比较详细的讨论.光纤传感器是一种新型和具有一定特殊应用的传感器,如光纤陀螺、光纤流量计等,由于其自身的特点,具有其他传感器无法替代的优势.在这些传感器中,光纤的选用是致关重要的,特别是传感器用光纤的特性及对光纤传感器的影响;本文提出了光纤传感器设计过程中选用光纤的一些重要依据并论及了发展传感器用光纤对光纤传感器的重要意义.     

光纤陀螺受辐照影响机理分析

构成光纤陀螺敏感器件的保偏光纤环在辐射环境中损耗会增加,陀螺的精度随之降低,从而限制了光纤陀螺在空间中的应用。采用60Co作为辐射源模拟空间辐射环境,对光纤陀螺及其光电器件进行了大量的试验,并对光纤陀螺及其光电器件受空间辐射影响的机理进行了研究,得出光纤陀螺光电器件中保偏光纤环受辐射影响最严重,从而重点分析了光纤陀螺敏感器件保偏光纤环的辐射影响机理,从原理上探讨了保偏光纤环在辐射条件下损耗的增加对光纤陀螺的影响,为光纤陀螺抗辐射加固技术提供了理论基础。     

谐振腔光纤陀螺光纤谐振环特性研究

对有限光源线宽情况下反射式光纤谐振环的响应特性进行了研究,得到了光纤谐振环各谐振特性参量的表示式.分析了特性参量与光源线宽和耦合器特性的关系,结合对方波调制谐振腔光纤陀螺极限灵敏度的分析,给出了设计高灵敏度谐振腔光纤陀螺光纤谐振环的要求和原则.进行了谐振腔光纤陀螺用光纤谐振环的实验研究,制作了适用于谐振腔光纤陀螺的高精细度和高谐振深度光纤谐振环.     

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。     

国产光纤实现直接抽运全光纤化3000 W级激光输出

基于国产光纤构建了直接抽运全光纤化主控振荡器功率放大器结构光纤激光器, 放大级分别采用武汉烽火锐光科技有限公司和中国电子科技集团公司第四十六研究所提供的国产20/400 μm掺镱双包层光纤作为增益光纤, 通过全国产化放大级实现了3050和3092 W的1080 nm激光输出. 放大级提取效率分别为67.3%和68.2%, 光-光效率分别为63.0%和63.9%. 据可查询资料, 这是公开报道的直接抽运全光纤激光输出的最高水平, 同时由于采用了国产光纤作为放大级增益光纤, 表明国产光纤具备了3 kW级光纤激光器输出能力. 通过国产光纤横截端面以及光纤熔接显微镜图像实验分析知, 光纤制造工艺的不足是导致国产光纤激光器效率低的主要原因. 继续改进光纤工艺, 提升抽运功率, 优化光纤长度, 有望实现更高功率的全国产化光纤激光器输出.     

一种实现高功率输出的新型光纤激光器

介绍了一种实现光纤激光器高功率输出的新方法--采用螺旋芯光纤,这种光纤是在光纤制作过程中按照一定的弯曲半径使纤芯呈螺旋状排布在光纤包层中.介绍了这种螺旋芯光纤的原理和其提高输出功率的能力,以及目前的理论与实验研究现状.基于该光纤,提出了一种光纤激光器相干合成新思想.     

抗弯光纤的理论研究与制造

针对军事上光纤制导等方面的技术要求,从光纤波导的芯层相对折射率差、芯直径、下凹包层等结构参数方面研究了光纤抗弯曲性能,并且研究了光纤内涂层对光纤弯曲性能的影响。通过对光纤弯曲特性的深入研究后,采用PCVD工艺制造了专利技术的抗弯光纤,并测试了相关参数。     

长余辉荧光粉发光特性的测试及实用装置

讨论了影响长余辉发光粉特性的主要因素。介绍了测试其发光特性的基本要求。在此基础上描述了一种测试长余辉荧光粉的新装置。它使用模拟D45光源作为激发光源，使用一台自动量程光度计来测量长余辉荧光粉亮度。从激发源到样品的激发光，以及从样品到光度计的发射光均由光纤进行传导。激发光通过耦合在二光纤中间的电动快门实施控制。装置的工作由计算机控制。需要特别指出的是装置可以在正常照明条件下工作。实测表明装置的设计非常巧妙和实用。     

Partially coherent optical waves in random gradient fibres

The excitation characteristics and spatial coherence of partially coherent optical waves in gradient fibres are demonstrated for incident light waves radiated from semiconductor lasers and light emitting diodes. Lower modes are efficiently excited in the case of coherent laser beams, while incident waves of low coherence such as lightwaves of LEDs excite higher modes. Pulse propagation of partially coherent optical waves in dispersive gradient fibres is also discussed for random index fluctuations. Mode coupled equations for temporal correlation functions of the electric field that are generalizations of coupled power equations are found. Mode filtering and pulse improvement with a lossy inhomogeneous cladding are described.     

光导在折射率引导光纤、多孔光纤、光子带隙光纤和纳米线中的简要定性解释

本文是一篇教学论文,旨在通过对具体实例中不同物理过程的分析来定性解释光导拓宽固体材料折射率引导光纤光谱、多孔光纤光谱、光子带隙光纤光谱和纳米线光谱的原理。     

Fibre Optical Parametric Amplification in Defect Bragg Fibres with Zero Dispersion Slow Light Effect

Nonlinearity enhancement by slow light effect and strong light confinement in defect Bragg fibres is demonstrated and anMysed in applications of fibre optical parametric amplifiers. Broadband low group velocity and zero dispersion as well as the strong light confinement by band gap enhances the nonlinear coefficient up to more than one order than the conventional high nonlinear fibres. Moreover, the zero dispersion wavelength of coupled core mode can be designed arbitrarily, under which the phase-matching bandwidth of the nonlinear process can be extended.     

Optical transmission of bulk plastic material and plastic lightguides at high optical powers

Optical transmission measurements were performed with bulk plastic materials and plastic fibres regarding the possible application as a transmission media for high optical powers. Transmission losses of PMMA bulk material and PS/PMMA core-cladding combination optical fibres were determined to be 0.757 dB m^-1 and 1.41 dB m^-1 at 514.5 nm, respectively. The core material of the investigated fibres withstands a power density of 3.8 x 10³ W mm^-2 when the light is suitably launched. With the light source available a transmitted cw output power of 2.1 W could be attained with a 1.5 m long fibre.     

Design and fabrication of Fourier plane diffractive optical elements for high-power fibre-coupling applications

In industrial processes using fibre beam delivery of high peak power laser light, diffractive optical elements are a very useful and flexible tool in maximising the amount of light reaching the work surface. This is due to the ability of diffractive optical elements to accurately couple light into multiple fibres, while conditioning the light in order to maximise the throughput for each fibre. We discuss the design techniques for diffractive optical elements and the application of these techniques to fibre-coupling problems. The flexibility of diffractive optical elements is demonstrated by their application to several fibre-coupling geometries, including a fibre bundle, a linear array of fibres, and a rotationally symmetric fibre connector. The diffraction efficiencies for the elements approach 90% with uniformity errors of less than 5%.     

Parametric processes in microstructured and highly nonlinear optical fibres

Optical parametric amplification is an important nonlinear process in photonic crystal fibres driven by the small effective area and the special dispersion characteristics of these fibres. Aside from its role in supercontinuum generation, parametric amplification can lead to efficient wavelength conversion, limited primarily by the uniformity of the diameter of currently available fibres. The related Bragg scattering process can be used for both wavelength conversion and optical switching, again limited by the physical characteristics of the fibres used.     

Determination of the refractive index of fibres using the modified area method: I. Homogeneous fibres

The mathematical formulae for determining the mean refractive indices and birefringence of homogeneous fibres are modified. This modification depends on calculating the area under the fringe shift and cross-sectional area of homogeneous fibres having nearly circular cross-sectional area taking the refraction of the incident light beam by the fibre into consideration. The mathematical analysis for two-beam and multiple-beam interferometric techniques is dealt with. These formulae are applied to polypropylene fibres with draw ratios of 3.5 and 4 using the two techniques. A comparison between the results when using the new formulae and when neglecting the refraction has been studied. The diffraction of a He–Ne laser beam is used for determining the shape of the cross-sectional area of these fibres. Microinterferograms are given for illustration.     

Observation of the optoacoustic effect in an optical fibre

The rediationless absorption of light propagating in optical fibres induces both stress waves and thermal waves in the fibre medium. Detection of such waves is termed the optoacoustic effect. Successful detection in optical fibres is easily obscured by scattered light impinging on the detector. We have obtained a signal of 2 mV on a piezoceramic transducer attached to a commercial step-index optical fibre after passage of a 1 J ruby laser light pulse along the fibre axis. No signal was, however, produced when the transducer was not in contact with the fibre. Similar results were obtained using chopped cw laser radiation but then more care had to be taken since the transducers used had a measureable sensitivity to the low frequency chopped radiation emitted perpendicular to the optical fibre axis.     

Determination of the optical and geometrical properties of fibres having skin–core structure

A method is suggested to determine both the refractive index and the transverse sectional shape and area of fibres, having skin–core structure, at the same time for the same region of the fibre. The method depends on using a fibre rotator device attached with Pluta polarizing interference microscope, to record the variation of the fibre thickness at each angle of rotation. Nylon 6 fibres having skin–core structure were used in this study. Beck-line method was used to determine the refractive index of the skin for light vibrating parallel and perpendicular to the fibre axis. To confirm the results of the suggested method, the optical microscope was used to determine the transverse sectional shapes of bundles of nylon 6 fibres. The mean refractive indices of the skin and core of nylon 6 fibres were determined. Microinterferograms are given for illustration.