An optical fibre sensor for use in a tissue cutting tool

This pre-study investigates a fibre optic alternative to more conventional sensors for measuring force indirectly as bending or deflection in a medical robotic application. The paper discusses problems regarding the integration of fibre optics into a cutting tool for the removal of prostate gland tissue. The aim is to integrate the sensor in a tube rod with an inner diameter of 0.6 mm and use it as a force feedback sensor for the control system of the robot. The paper proposes and evaluates an inexpensive opto-mechatronic device for launching light into and detecting light received from an optical fibre. A simple sensor prototype is constructed to show the feasibility to use a fibre optic sensor for the prostate gland cutting tool.     

LED-based fibre optic oxygen sensor using sol-gel coating

An intrinsic evanescent wave fibre optic sensor for oxygen is reported. The sensor is based on the quenching of fluorescence from a ruthenium complex trapped in the cage-like structure of a sol-gel-derived porous film on a de-clad section of multimode optical fibre. The sensor exhibits excellent performance using blue LED excitation and silicon photodiode detection, and establishes the viability of low-cost portable sensor devices based on the sol-gel process. Gas phase measurement data over the range 0-100% oxygen exhibit high signal-to-noise ratio (~150), good repeatability and short response time (<5 s)     

Polarisation-insensitive fibre optic Michelson interferometer

A polarisation-insensitive fibre optic Michelson interferometric sensor configuration is demonstrated. The approach is based on the use of birefringence compensation in a retraced fibre path using Faraday rotator mirror elements.<>     

FONI-SPATE: A new fibre optic stress/strain sensor, using anear-infrared variant of the SPATE effect

A new fibre optic stress/strain sensor, for monitoring hot materials is reported. The fibre collects grey body emission from a heated material sample. When the sample is subjected to transient stresses, the radiation is modulated due to the adiabatic changes in its temperature. The modulation is monitored, via a silica fibre, using a near-infrared GaInAs photodetector. This is also believed to be the first demonstration of the SPATE method in the near infrared     

Strain sensing based on coherent Rayleigh scattering in an opticalfibre

A fibre optic strain sensor based on Rayleigh backscatter using a time division multiplexing scheme with an optical pulse is presented. The sensor has a gauge length of <0.5 m and a strain sensitivity of <1 nϵ/√Hz at 2 kHz     

Novel fibre optic gyroscope with a configuration combining Sagnac interferometer with fibre ring resonator

A novel fibre optic gyroscope, with a structure making use of the combination of a Sagnac interferometer with an active fibre ring-resonator, is proposed and analysed. The proposed gyroscope can be viewed as a generalised structure of the conventional Sagnac interferometric type fibre optical gyroscope. It has the advantages of both long fibre loop length and multipath interferences. By inserting a fibre amplifier in the loop to provide an optical gain of several dB, the relative maximum sensitivity is enhanced to approximately 30 times more than that of conventional Sagnac interferometric fibre optic gyroscopes.<>     

Detection of solvents using distributed fibre optic sensor

A fibre optic sensor that is capable of distributed detection of liquid solvents is presented. Sensor interrogation using optical time domain reflectometry (OTDR) provides the capability of locating solvent spills to a precision of /spl plusmn/2 m over a total sensor length that may extend to 20 km.     

光纤有源内腔激光传感网络技术

提出了一种新的光纤气体传感网络的有源复用系统 ,将锁模激光技术与光纤环形内腔激光气体传感技术相结合 ,提出并实现一套以锁模光纤环形腔激光器为复用基础的光纤内腔激光气体传感网络系统 ,此传感网络系统可同时对多个气体传感单元进行高灵敏度测量     

Optical waveguide sensor using evanescent wave excitation of fluorescent dye in sol-gel glass

The sol-gel process for low temperature fabrication of porous glass has been used to entrap chemically-sensitive dyes for optical sensor applications. Evanescent wave excitation was used to examine the behaviour of an unclad fibre which was dipcoated with a thin layer of porous cladding within which a pH-sensitive dye was entrapped. The performance of the pH sensor is reported and the potential of the technique for distributed and integrated optic sensing is discussed.<>     

新一代塑料光纤接入网

光纤接入技术是最有前途的宽带接入技术,实现光接入网的最终目标是光纤到办公室(FTTO)和光纤到用户(FTTH)。从光纤接入网的基本结构及其类型出发,讨论了塑料光纤在短距离通信中的优势和它在楼宇用户网络方面的应用,指出塑料光纤接入网是新一代光纤接入网的一个发展方向。     

应用于折射率检测的光纤表面等离子体波传感器的研究

光纤表面等离子体波传感器具有结构简单、灵敏度高等特点,在机敏结构中具有非常重要的应用前景。运用光纤表面等离子体波来测量折射率是一种简便、灵敏的方法,我们可以利用这一特性制作出通过检测折射率对复合材料进行固化检测的光纤表面等离子体波传感器。本文介绍了光纤表面等离子体波传感器的基本原理及利用这种光纤传感器来测量折射率的初步研究。     

基于光楔的光纤法-珀应变传感器解调系统原理研究

根据基于光楔的光纤法-珀应变传感器解调系统的结构,分析了解调系统的解调原理,并给出了仿真结果.得出当光楔厚度与法-珀传感器腔长相等时,其输出光强最大.通过实验结果与仿真结果的比较,说明基于光楔的光纤法-珀应变传感器解调系统在原理上是正确的.     

SMS fibre structure for temperature measurement using a simple intensity-based interrogation system

A singlemode-multimode-singlemode (SMS) fibre structure for temperature measurement that utilises a simple intensity-based interrogation system is proposed. The temperature dependence of the SMS fibre structure utilised as a sensor is investigated numerically and experimentally. It is found that a strong temperature dependence for the SMS fibre structure exists at selected wavelengths. The temperature characteristic at such wavelengths is linear in nature and can be used for temperature measurements. The proposed temperature sensor offers a high resolution and accuracy, and also benefits from a simple configuration and low cost when compared to other fibre-optic temperature sensors.     

Simple fibre-optic sensor for detecting water penetration into optical fibre cables

In this sensor concept a graded-index fibre is pressed on a periodic structure by a material that swells in water, causing microbending loss. Optimum values of the wavelength of the periodic structure are calculated and confirmed by measurements. The sensor can easily be integrated in an optical fibre cable; water penetration can then be localised by OTDR.     

缆索拉力光纤微弯传感器及其非线性补偿

缆索拉力监测对相关行业的安全生产具有重要意义。提出一种新型缆索拉力光纤微弯传感器,介绍了带有弹簧的传感器结构,给出了传感器力学传递函数关系式,通过对梯形弹簧的非线性特性分析,说明梯形弹簧可用于缆索拉力光纤微弯传感器的非线性补偿。实验测试结果表明,经过梯形弹簧非线性补偿的缆索拉力光纤传感器可以获得很好的线性响应。该缆索拉力光纤传感器可应用于电梯、塔吊、起重机、空中索道等场合的拉力监测。     

单频光纤激光器相位噪声的影响因素

单频光纤激光器是光纤通信中最具前途的一种光源,在光纤传感、激光雷达和激光测距等方面具有重要的应用,而相位噪声是衡量其性能的关键指标之一。采用示波器和动态信号分析仪方法对单频光纤激光器的相位噪声进行测量。利用功率谱、积分谱对不同泵浦源功率、种子源功率和波长的光纤激光器的相位噪声进行定性分析,结果表明:泵浦功率越大,低频相位噪声所占比重越大;而对于不同种子源功率,相位噪声在测试频段的比例基本处于同一水平;对于测试的不同种子的波长,相位噪声高频段所占比例不同,其中种子波长为1 560.48 nm比例最大。     

利用双激光光源监测甲烷浓度的光吸收法光纤传感器

基于Lamber -Beer定律 ,利用波长为 1.3 3 μm的脉冲lnP/InGaAsP半导体激光器作为测量光源 ,用低损耗的光纤进行光信号的传输并以钽酸锂热释电探测器作光电转换器件 ,设计出了一种新颍的远距离监测甲烷浓度的光纤传感系统。以此光纤传感系统为探头 ,设计出了一种可实时监测甲烷浓度的仪器 ,并能实现 3km的远距离遥测。介绍了该光纤传感系统及由该光纤传感系统构成的监测仪器的基本结构与工作原理 ,讨论了其中的技术难点及其相应的解决方法 ,并给出了监测仪器相应的技术指标     

PMD指标对光纤的影响

随着光纤系统的改进及未来通信系统剧增的需要，长距离，多信道，高数据率光纤系统的运用越来越普及，光纤偏振模散（PMD）的影响也越来越显著，就光纤的PMD指标进行论述，为光纤系统设计，提高光纤系统性能，把PMD纳入系统设计考虑之列年代一种方法。     

光纤倏逝波化学传感器灵敏度特性研究

为了克服传统光纤化学传感器的不足,运用宽光谱分析法设计一种基于倏逝波原理的光纤化学传感器,研究了传感器的几何结构参数,溶液浓度与灵敏度的关系。运用光束传播法(BPM)分析传感器几何结构参数与灵敏度的关系;通过化学腐蚀方法制备出不同参数结构的传感器,并用不同浓度亚甲基蓝溶液对这些传感器进行实验验证。实验结果表明,模拟结果与实验结果相符,溶液浓度越大,传感区纤芯越细、越长,灵敏度越高;文章提出的光纤倏逝波化学传感器在水质检测方面有着潜在的应用。     

本征型光纤倏逝波化学传感器的研究

为了克服传统光纤化学传感器的不足,本文提出基于倏逝波原理的本征型光纤化学传感器。根据光线理论数值分析了传感器几何结构参数,溶液折射率与灵敏度的关系。通过化学腐蚀方法制备出不同参数结构的传感器,进行实验系统设计,并用不同浓度亚甲基蓝对这些传感器进行了实验研究。实验结果与数值计算结果一致,传感区纤芯越细,越长,其灵敏度越高。为了提高传感器灵敏度并保证纤芯不至于太细而折断,应少减小传感器直径,有效增加其长度。