激光在光纤直径测量与控制中的应用

本文介绍光纤直径动态测量中采用的激光扫描技术以及纤径控制中采用的逐点比较式新技术.对于直径为50～250微米的光纤,测量误差在±0.5%以内.结果以数字形式显示,并转换成模拟信号,有效地控制光纤拉丝机的拉丝速度,从而保证了光纤直径均匀.     

模糊控制在光纤拉丝机中的应用

文章提出一种基于单片机的光纤拉丝机模糊控制方法.系统以激光测径仪为反馈元件,单片机为模糊控制器实际载体,制定出基于专家系统的控制规则,实现了对光纤拉丝机的闭环控制.应用结果表明,该控制系统运行结果达到控制要求,具有良好的实用性和推广价值.     

非接触式激光检测技术及在PCB行业中的应用

随着工业技术水平的发展,自动生产线大量应用,新技术和顾客对产品的质量提出了更高的要求,所以现代工业越来越需要非接触式的测量,而激光测量就提供了这样的方式。本文阐述了激光测量的原理、特点、好处以及在PCB制造中的一些应用。     

光纤损耗谱工程全场景再现教学实验系统

光纤损耗特性是“光纤通信原理”课程必须要掌握的关键知识点。为了让学生更形象直观的学习损耗谱知识，本课程将工程测量和标定方法植入到课程实验教学中，利用工程全场景再现的理念，设计了一套全新的光纤损耗谱测量实验系统，系统测量光纤在700-1750 nm波长范围内的损耗谱，学生通过光路设计、连接、计算机拟合、绘制曲线等多个操作步骤，融入到工程实测场景中，更好的掌握光纤损耗理论知识。     

Optical fiber drawing method with gas flow controlling system

A method for reducing the diameter variation of optical fibers during fiber drawing is described. The method is based on the control of gas flow and drawing speed. Rapid fluctuations in diameter are suppressed by adjusting the gas flow rate, and slower ones are controlled by changing the drawing speed. The efficiency of this method has been tested by applying stepwise disturbance of ±63% in preform feeding speed. Fluctuations of fiber diameter are controlled within ±1 μm despite the forced disturbance. By applying this method to high-speed drawing (30 m/min), a high-tensile-strength fiber, with diameter fluctuations within ±1 μm and transmission losses near the 0.85-μm wavelength region of approximately 3 dB/km, is achieved     

浅析大尺寸光纤预制棒(OVD法)的制备工艺

光纤预制棒的大型化是降低光纤拉丝成本的必要手段,本文介绍了利用OVD法生产大尺寸光纤预制棒的工艺方法,主要包括大尺寸光纤预制棒在沉积、烧结、保温过程中的设备与工艺介绍.     

Fabrication of microstructured optical fibers-part I: problem formulation and numerical modeling of transient draw process

Microstructured optical fibers (MOFs) achieve their desired performance via a pattern of holes that run along the length of the fiber. Varying the hole pattern allows a variety of optical effects to be produced. However, the original hole pattern within the preform may not be accurately transferred to the finished fiber due to the combined impact of material properties and the drawing conditions experienced during fabrication. In this two-part paper, the processes of drawing MOFs having arbitrary cross-sectional hole structures will be analyzed for the case of Newtonian materials. Part I presents a modeling formalism to describe the drawing processes, followed by a scaling analysis on a representative case, i.e., the nonisothermal drawing of an axisymmetric annular hollow fiber, to reveal the major factors influencing the drawing of both silica and polymer MOFs. By treating the primary draw process (i.e., from preform to intermediate cane) in fabricating polymer MOFs as a transient, isothermal problem, numerical simulations were carried out for an illustrative five-hole structure. The results revealed the central importance of any steep neck-down region on hole-shape deformation as well as the importance of forces additional to those associated with surface tension effects. Both experimental observations and numerical modeling show that a diversity of hole "activities" (both in a hole's relative size and shape) can occur when drawing MOFs. Part II will extend both the analysis and numerical modeling with a focus on the steady-state continuous draw process (i.e., from preform or cane to fiber). In parallel with this analysis, we also present experimental results for the drawing of polymethylmethacrylate (PMMA) MOFs.     

Towards global information networking

An overview is given of how fiber optics technology has emerged from the drawing board into the marketplace over the last, roughly, 25 years, and how the low-cost bandwidth that fiber provides enables bandwidth-intensive applications such as access to multimedia information, customized television programming, and multimedia real-time communications and messaging. A prognosis for future applications in the environment of broadband, personalized communication services is also given     

油田测试中的光纤传感技术

指出了目前油田井下多相流、压力、温度、声波以及核等储层参数测试的意义和所面临的问题，介绍了光纤传感技术以其独特的优势和在这些参数测试中的广泛应用。最后展望了光纤传感器在油田测试中的应用前景。     

折射率引导型微结构光纤的奇异非线性效应和应用

折射率引导型微结构光纤不但有很多新颖的色散特性,而且还有很高的等效非线性系数,这两者相结合赋予RG-MOF很多独特的基于非线性特性的应用。介绍这种光纤中所产生的强非线性效应,如超连续谱生成、三次谐波生成和光学孤子生成等,然后参照最新的研究报道介绍其最新应用,如MOF波长转换器、高速信号分离器、基于SC分离的多信道脉冲源。     

Local Birefringence in Unidirectionally Spun Fibers

The application of a spinning step in the drawing process is known to improve optical-fiber polarization mode dispersion. For a more comprehensive understanding of the mechanism through which spinning modifies fiber performances, in this paper, the authors investigate the effect of unidirectional spinning on local fiber birefringence in terms of the effectiveness of spin-function transfer and reduction of the local intrinsic birefringence under different drawing conditions. The actual frozen-in spin is experimentally recovered by means of a cut-back procedure. Different from the case of a periodic spinning, a unidirectional spinning correctly reproduces the nominally imparted spin rate in agreement with theoretical modelizations of the transfer effectiveness of the spinning process. A theoretical explanation for the experimental evidence, recently proved by tomographic stress measurements, of spinning affecting fiber linear intrinsic birefringence is provided. In particular, the interaction of drawing parameters and spinning process in defining stress development into fibers is considered. To validate the proposed model, further tomographic reconstructions of stress profiles in fiber spun at different rates and drawing speed were carried out. Besides, corresponding stress-induced birefringence values were estimated and compared with those recovered by the cut-back technique. Variations of spun fiber beatlength values with respect to the unspun case, as obtained from both measurement techniques, are in good agreement, providing a further reliable confirmation that an improvement of the beatlength may proceed as a consequence of the applied spin     

基于3dB光纤耦合器构成的Mach-Zehnder光纤干涉仪稳定控制系统

Mach-Zehnder光纤干涉仪（MZI）是一种利用光干涉原理制成的仪器,具有体积小、重量轻、结构紧凑、抗电磁干扰和灵敏度高等优点。但是,Mach-Zehnder光纤干涉仪是一种非平衡并行结构,易受环境等因素影响导致其性能不稳定。因此,高性能测量系统和通信系统对光纤干涉仪的稳定工作提出了严格的要求。提出了一种基于3 dB光纤耦合器构成的Mach-Zehnder干涉仪的稳定控制系统,其目的是通过对探测器的输出信号进行调制,并反馈到光纤干涉仪的一臂上进行偏置控制,从而实现Mach-Zehnder光纤干涉仪的稳定工作。该方法实现简单,克服了现有3 dB光纤耦合器构成的Mach-Zehnder光纤干涉仪不能稳定工作的问题。     

Fabrication of optical waveguides by the outside vapor deposition process

The outside vapor deposition process (OVD) represents one of the principle vapor deposition methods used to make glass fiber optical waveguides [1], [2]. In this brief review, each of the basic process steps (deposition, sintering, drawing) are described and the present performance capabilities are presented. Process improvements leading to hydroxyl removal, increased numerical aperture (NA), and long wavelength operation are discussed. Selected examples of fiber compositions and properties are tabulated which range from high-NA fibers suitable for short-distance applications through very-high-performance fibers for long-distance transmission.     

光纤环形镜在光纤通信中的应用

介绍了光纤环形镜的工作原理,讨论了近年来其在高速光开关,波分复用器以及特性测量等领域的若干应用研究.     

光纤拉丝机一机两炉的设计改造

改造方案是在原进口中频感应加热炉拉丝机上再加装一台石墨加热炉,使之成为一机两炉工作状态,同时在一台电脑控制下,使用同一拉丝控速系统,可在同一主体设备上分别将大,小直径规格的预制棒拉制成光纤.     

高功率双包层光纤放大器

高功率双包层光纤放大器在光纤传感、光纤通讯、光谱测量和惯性约束聚变等领域有广泛应用.介绍了两种获得放大激光输出的高功率双包层光纤放大器:单频双包层光纤放大器和脉冲双包层光纤放大器.分析了它们的工作原理及关键技术,并对国内外近期进展作了综述.     

窄线宽光纤激光器进展

窄线宽光纤激光器在光纤传感、激光倍频、光谱测量等领域有广泛应用。简单介绍了窄线宽光纤激光器的研究进展．详细阐述了窄线宽光纤激光器的各种腔形结构及线宽压缩机制，并对各种方法作了简要的对比。     

Stress measurements of fibers and preforms

The authors point out the formation mechanism of axial stress, describes the method and the apparatus used for measurements, and presents the results obtained during a study of loss reduction on trapezoidal core 1.55-μm dispersion-shifted fibers manufactured by the MCVD technique. It is concluded that the stress measurements on fiber are less accurate than those on preform (experimental dispersion reaches 15% instead of 5%). The various observations made from measurements on preform show that the axial stress is related to the index profile and that the core axial stress increases with the GeO₂ content. The measurements performed on fiber show that the level of stress is linearly dependent on the drawing tension and that the stress profile is related to the glass-transition temperature of the different materials. Furthermore, this method of stress measurement is complementary to the more standard index profile measurement on fiber or on preform     

Single-polarization single-mode optical fibers

Strictly speaking, an ordinary axially symmetrical single-mode fiber is a "two-mode" fiber because two orthogonally polarized HE11modes can be propagated in it. This fact results in the instability of the polarization state of the propagated mode when geometrical perturbation exists in the fiber, and also the so-called polarization mode dispersion. These are harmful in some applications of single-mode fibers to communication and measurement. To prevent these adverse effects, single-polarization single-mode (SPSM) optical fibers have been developed. Three basic types of the SPSM fiber are elliptical-core fiber, stress-induced birefringent fiber, and side-pit fiber. This paper describes the principles of these three types, performance obtained experimentally, theoretical approaches, and measurement techniques related to the SPSM fibers. Finally, relevant technical tasks in the future are mentioned.     

相位敏感OTDR和布里渊OTDR结合的双参量分布式光纤传感的研究

在分布式光纤传感及应用中,单一传感系统一般只能实现一种参量的监测,如相位敏感光时域反射计(Φ-OTDR)只能监测光纤沿线的振动信息,布里渊光时域反射计(BOTDR)仅能监测应变/温度信息.对于多参量监测的应用场合,必须通过配合多种技术和系统来实现多参量监测和分析,增加监测成本和复杂性.设计并搭建了一种集成Φ-OTDR和...