交叉绕制单模光纤环减小轴向磁场灵敏度

垂直光纤环面变化的轴向磁场会降低去偏陀螺的精度,因此提出减小轴向磁场灵敏度的新方法:用交叉绕法单模光纤环作为敏感环。与普通绕法相比,理想交叉绕法光纤环中的正反任一束光经过的路径可分为相等的两段,每段路径上产生的Faraday相位延迟大小相等、符号相反,整个路径上相互抵消,从而两束光不存在与磁场有关的Faraday非互易相位差。仿真结果表明,交叉环有很低的轴向磁场灵敏度,与轴向磁场灵敏度为23.4°/(h·mT)的普通环相比,其他参数相同、不对称度为1%的交叉二极子光纤环,轴向磁场灵敏度仅为0.23°/(h·mT)。     

绕制变压器和滑线电阻的两种自动绕线机

大冶钢厂计器计最车间元件组的老工人和技术人员自己动手修旧利废,制成用于绕制变压器线包和绕制电子电位差计环状滑线电阻专用的两种自动绕线机,不仅提高了绕线质量,而且提高了工效,减轻了劳动强度。这两种绕线机(见图1和图2)都由绕线机架、     

基于光电缆的分布式温度传感网络的实验研究

本文提出增加一根光纤光栅与光电缆绕制在一起,用于监测电缆中的实时温度.采用有限元分析方法,建立了光电缆温度场模型.使用可调谐脉冲激光为光源,在一根光纤上刻制多个相同中心波长的布拉格光栅,即采用全同光栅作为系统的温度传感器,当光电缆线路中温度发生异常时,反射回来的光栅中心波长发生偏移,通过检测反射光中心波长发生的偏移量可...     

交错绕法在开关电源变压器中的应用

本文主要介绍了一种交错绕制的开关电源变压器绕法及其应用。以反激式变压器初次级交错绕制降低漏感、谐振式变压器初次级交错绕制提升输出功率等为例,阐述了其原理及作用。     

电阻绕线机的设计与改进

针对国内电阻绕线机绕制阻值不精确的问题,本文介绍了一种通过测径仪和PLC控制精密绕制电阻的系统。系统以测径仪和PLC可编程控制器为核心,使绕制的电阻阻值精度较普通方法大为提高,并且通过修改参数可以绕制不同标定阻值的电阻;该系统提供了友好的人际交互页面,使操作简单方便。     

瓦楞纸板垛的自动绕绳打结机设计及试验

目的为了解决瓦楞纸板生产线后端纸板垛自动捆扎问题,设计一种自动捆扎设备。方法针对绕绳打结等要求,选用经济实惠、轻便灵活的塑料绳,由此设计、试验、制造出能对瓦楞纸板垛进行绕绳、打结动作的机构。结果设计的自动绕绳打结机构使用电机、气缸驱动,替代人工对瓦楞纸板垛进行自动捆扎,降低了劳动强度,工作效率明显提高。结论所设计的自动绕绳打结机构能满足瓦楞纸板的捆扎要求,降低了人工成本,提高了生产效率,具有良好的应用前景。     

基于虚拟仪器的光纤多参数自动校准测试平台

针对原有光纤参数测量设备独立测试、测量效率低、光纤接口多次插拔等缺点,设计开发光纤多参数自动校准测试平台。采用LabVIEW编程平台,将多台光纤参数测量设备互联,集中控制,自动设置测量参数,引入4×4光开关矩阵,自动切换光路,避免光接口的多次插拔,以光功率计、光源的校准为例,编写自动校准程序,自动记录校准结果,自动生成校准报告。实际使用结果表明:该平台校准测试效率高,功能拓展便捷,具有一定的应用前景和推广价值。     

光纤复绕机噪声治理

高速旋转的光纤复绕机,复绕速度为Am/min噪声为83.2dB(A),当复绕速度提高7%后,噪声为84.8dB(A),复绕速度提高14%后,噪声将达到86.2dB(A),通过对复绕机筛选轮进行动平衡校正以及对复绕机进行隔声和吸声处理后,当复绕速度为A时,噪声降低了8.7dB(A）,为声源降噪提供了新的经验。     

多波长掺镱光纤激光器实验研究

为了产生室温下掺镱光纤激光器稳定的多波长激光振荡,采用两个光纤环镜作为线形腔掺镱光纤激光器的端镜,在其中一个环镜中熔接一段保偏光纤构成梳状滤波器,通过优化掺镱光纤长度和腔损耗,实现了室温下1060nm附近稳定的多波长振荡.实验结果表明,在室温下,掺镱光纤存在比较明显的非均匀加宽效应,从而使得激光器的振荡波长数随泵浦功率的增加而增加.     

城域网光纤通信自动保护系统方案分析

为了提升石油勘察的通信效益,进行局域网光纤通信系统的健全是必要的,这需要进行光纤备份模块的开展,更好的进行光纤应用模块的控制。基于此,本文对城域网光纤通信自动保护系统方案进行了研究,分析了光纤通信网保护系统模块,研究了光纤通信网自动保护模块的选择。     

Mode-hop-free single-longitudinal-mode erbium-doped fiber laser frequency scanned with a fiber ring resonator

We describe the experimental construction of a single-longitudinal-mode erbium-doped fiber ring laser equipped with a ring resonator filter. The system is designed to avoid mode hopping and can be frequency scanned for spectroscopic sensor applications. We modified a conventional ring resonator filter to have the capability to reduce transmittance of unwanted modes, which is essential for frequency scanning without mode hopping.     

Double spacing multi-wavelength L-band Brillouin erbium fiber laser with Raman pump

A new multi-wavelength Brillouin erbium fiber laser (BEFL), which operates in the L-band region with double frequency Brillouin spacing, is demonstrated. This design uses a Raman pump (RP) and a piece of 2?km highly nonlinear fiber as a gain medium. The double frequency spacing is achieved by employing a dual ring configuration, which is formed by utilizing a four-port circulator that removes the odd-order Stoke signals. Twenty Stokes and seventeen anti-Stokes lines, which have optical signal to noise ratio (OSNR) greater than 15?dB, are generated simultaneously with a spacing of 0.16?nm when Brillouin pump and RP powers were fixed at the optimum values of 8 dBm and 40?mW, respectively. The BEFL can be tuned in the range between 1591?nm to 1618?nm. The proposed configuration increases the number of lines generated and the OSNR, and thus allows a compact multi-wavelength laser source to be realized.     

Measuring optical fiber length by use of a short-pulse optical fiber ring laser in a self-injection seeding scheme

A method for measuring the length of an optical fiber by use of an optical fiber ring laser pulse source is proposed and demonstrated. The key element of the optical fiber ring laser is a gain-switched Fabry-Perot laser diode operated in a self-injection seeding scheme. This method is especially suitable for measuring a medium or long fiber, and a resolution of 0.1 m is experimentally achieved. The measurement is implemented by accurately determining the pulse frequency that can maximize the output power of the fiber ring laser. The measurement results depend only on the refractive index of the fiber corresponding to this single wavelength, instead of the group index of the fiber, which represents a great advantage over both optical time-domain reflectometry and optical low-coherence reflectometry methods.     

A miniaturized sensor consisting of concentric metallic nanorings on the end facet of an optical fiber

A polarization-independent optical sensor is created by fabricating a concentric gold ring grating with a period of 900 nm on the end facet of an optical fiber. The sensing function of this miniaturized device is realized by sending white light as a probe to the gold rings and collecting the response signal in the back-reflection through the optical fiber. A pronounced peak due to the Rayleigh anomaly of the gold ring grating is observed in the reflection spectrum, the center wavelength of which is sensitive to the change in the environmental refractive index of the fiber end facet. Theoretical analysis not only shows excellent agreement with the experimental results, but also gives insights into the mechanisms of this kind of sensor. Using the center position of the Rayleigh peak as the response signal, a high sensitivity dλ/dn of 900 nm per unity refractive index is realized for this sensor and a resolution of Δn/n ≈ 1% is demonstrated in preliminary experiments. The sensitivity is solely determined by the period of the grating.     

Theory of a tunable fiber ring depolarizer theory

The depolarizing properties of a fiber ring structure have been analyzed, and the analytical solution to the device optimization has been found. The result proves that a tunable fiber ring depolarizer can completely depolarize light for any input state of polarization.     

短腔的高浓度掺铒光纤激光器

本文提出采用高浓度掺铒光纤的短腔环形光纤激光器,研制出铋铝共掺和铋镓铝共掺两种石英基高浓度掺铒光纤,这两种掺铒光纤的吸收系数在1530 nm处分别达到了66.3dB/m和59.5dB/m.利用这两种石英基高浓度掺铒光纤,采用环形结构制作出了短腔的光纤激光器,光纤激光器中铒光纤长度分别仅为30 cm和90 cm.对采用这两种高浓度掺铒光纤制作的光纤激光器的输出特性进行了测试和分析.实验结果表明,采用铋镓铝共掺的掺铒光纤制作的光纤激光器具有更高的输出功率和斜率效率,在980 nm泵浦源输出功率330 mW时可以实现15 dBm的激光输出,激光器的斜率效率达到了22%.     

苎麻纤维布和玻璃纤维布混杂铺层复合材料的力学性能

利用真空吸注成型(vacuum resin absorbable molding,VRAM)工艺制备苎麻纤维布与玻璃纤维布混杂铺层的环氧树脂基复合材料。测定复合材料的损耗因子、储能模量的温度谱和力学性能;利用单悬臂梁共振实验测量复合材料的共振频率和自由振动衰减曲线并计算出了阻尼因子。用有限元软件对其共振频率和自由振动衰减实验进行仿真分析。结果表明:通过苎麻纤维布/玻璃纤维布的混杂铺层,能够实现材料阻尼性能和力学性能的可控调节,充分发挥复合材料可设计性强的优势。其中RGR铺层的复合材料的损耗因子比纯玻璃纤维板提高了1.4倍,而拉伸强度比纯苎麻纤维板提高了3倍多;自由振动的有限元模拟曲线和实验曲线基本吻合,表明可以通过模拟软件实现复合材料的虚拟振动测试,从而为材料性能预测和设计提供方便。     

High efficiency terahertz-wave photonic crystal fiber optical parametric oscillator

We theoretically propose phase matched terahertz (THz)-wave generation via degenerate four-wave mixing (FWM) in a fiber optical parametric oscillator (FOPO) with our newly designed photonic crystal fiber (PCF). Perfect phase matching is realized when we locate the pump wavelength in the normal group-velocity dispersion (GVD) regime. The generated THz-wave can be tuned from 4.7578 to 5.9015?THz by varying the pump wavelength. Moreover, peak power of 27.38?W at 5.9015?THz with conversion efficiency of 1.37% is realized when the pump peak power of 2000?W is at 4.675?μm in our FOPO.     

Rangeability extension of fiber-optic low-coherence measurement based on cascaded multistage fiber delay line

We demonstrate a simple method to extend the measurable fiber length with a fiber-optic low-coherence technique. This method is based on a cascaded structure of multistage fiber delay line laid in one arm of the low-coherence technique. By choosing different individual stages in the cascaded fiber delay line, the length of the fiber under test can be continuously measured with a different measurement range. The measurement range of 0.81 km and spatial resolution of 60 μm are successfully realized.     

Ringing phenomenon of the fiber ring resonator

A resonator fiber-optic gyro (R-FOG) is a high-accuracy inertial rotation sensor based on the Sagnac effect. A fiber ring resonator is the core sensing element in the R-FOG. When the frequency of the fiber ring resonator input laser is swept linearly with time, ringing of the output resonance curve is observed. The output field of the fiber ring resonator is derived from the superposition of the light transmitted through the directional coupler directly and the multiple light components circulated in the fiber ring resonator when the frequency of the laser is swept. The amplitude and phase of the output field are analyzed, and it is found that the difference in time for different light components in the fiber ring resonator to reach a point of destructive interference causes the ringing phenomenon. Finally the ringing phenomenon is observed in experiments, and the experimental results agree with the theoretical analysis well.