High-speed fibre Bragg grating sensor interrogation using dispersion compensation fibre

A novel high-speed fibre Bragg grating (FBG) sensor interrogator using dispersion-compensating fibre is proposed and demonstrated. The wavelength shift measurement of the FBG sensor is converted to time-domain measurement. The high-speed potential of this scheme was investigated experimentally, demonstrating an effective sampling speed of 2.44 megasamples per second.     

Sensor interrogation technique using chirped fibre grating basedSagnac loop

A novel and simple sensor interrogation scheme for fibre Bragg grating (FBG)-based sensing systems is demonstrated. In this scheme, a chirped FBG-based Sagnac loop is used as a wavelength-dependent receiver, and a stable and linear readout response is realised. It is a significant advantage of this scheme that the sensitivity and the measurement wavelength range can be easily adjusted by controlling the chirp of the FBG or using an optical delay line in the Sagnac loop     

Matched-filter interrogation technique for fibre Bragg gratingarrays

A technique for the demodulation of fibre Bragg grating (FBG) sensor arrays that uses a matched grating array to optically filter and track wavelength shifts from the FBG sensors is demonstrated. The use of matched grating arrays in the serial configuration represents an efficient and potentially low-cost interrogation technique for FBG sensors     

New simple one-end splice loss measurement method using an OTDR for single-mode optical fibre

The letter presents a new simple method using an optical time-domain reflectometer for measuring the real splice loss of single-mode optical fibres from one end of the fibre. Importantly, the method eliminates the difference in backscattering properties of the spliced fibres by subtracting two discontinuities obtained at different wavelengths in the received backscattered power.     

Simultaneous measurement of strain and temperature using single tilted fibre Bragg grating

Tilted fibre Bragg grating (TFBG) with grating planes tilted at an angle of 3deg corresponding to the fibre axis shows core mode and a large number of cladding-mode resonances in its transmission. Discriminating temperature and strain simultaneously using a single tilted fibre Bragg grating is proposed and demonstrated experimentally. The wavelength shifts of the TFBG in response to temperature and strain are investigated. The results show that the cladding modes and core mode have different strain sensitivities while the temperature sensitivities are equal. So, it is possible to monitor the core-mode resonance and the cladding-mode resonances of the TFBG spectrum, allowing the separation of the temperature and strain induced wavelength shifts.     

光纤光栅温度和应变同时测量技术研究进展

分析了光纤光栅温度、应变同时测量原理,综述了光纤光栅传感器温度、应变同时测量技术现状,并对其分别进行了分析,总结了其优缺点.最后对其技术前景进行了展望.     

Simultaneous temperature and lateral force measurement using simple arc-shaped FBG sensor module

An arc-shaped fibre Bragg grating (FBG) sensor module, containing a pair of FBGs is constructed, which enables simultaneous temperature and lateral force measurements. Experimental study of a module, with such a structure, shows good agreement with theoretical analysis     

Transmission/reflection analysis for distributed optical fibre losssensor interrogation

A novel interrogation method for fibre optic loss sensors based on the analysis of transmitted and reflected powers of a continuous wave light source is presented. The position of the loss region is determined from unique dependencies between normalised powers for different locations of the disturbance along the fibre containing a number of Bragg gratings     

Liquid-core optical fibre for voltage measurement using Kerr effect

Liquid-core optical fibre for voltage measurement, based on the Kerr effect, is shown. The measurements are performed for 50 Hz alternating voltage, i.e. for 23?130 kV/m electric fields.     

Self-mixing based interrogation techniques for high-reflectivity fibre Bragg grating sensors

A novel interrogation technique for fibre Bragg gratings, based on the self-mixing effect in strong feedback regime and intensity detection, is demonstrated through experimental measurements. The application of an appropriate spectral estimator permits transferring the analysis into the frequency domain, leading to the realisation of a power drift-tolerant strain sensor.     

Remote temperature sensing using polarisation-preserving fibre

A fibre-optic temperature sensor is described in which the change in modal birefringence of a short length of polarisation-preserving fibre is monitored in reflection through a 90 m length of input fibre. The system shows high sensitivity and good downlead insensitivity.     

Baseband-frequency-response measurement of graded-index fibre using step-index fibre as an exciter

For measuring reproducibily the baseband frequency response of a graded-index fibre, a mode exciter utilising an ordinary step-index multimode fibre has been proposed. The input mode power distribution and the frequency response of the fibre with the exciter are altered very little for axis offset. Input mode distribution excited indicates that excitation of nearly all modes takes place.     

一种实用化实时测温系统的测温灵敏度

基于基尔霍夫定律,利用半导体激光器InGaAs/I及钽酸锂热释电探测器设计了一种实用化的实时测温系统。基于该系统A/D转换器件的分辨率、V(T)-T曲线的温度灵敏度及其与测温范围间的制约关系,确定了系统应选用16位的芯片为其A/D转换器件;基于该系统的测温精度、V(T)-T曲线的相对温度灵敏度及其与波长间的关系,对其工作波长的优化选择进行了进一步的讨论;基于探头的温度分辨力、A/D转换器件的分辨率以及与V(T)-T曲线的温度灵敏度间的制约关系,对其波长带宽的优化设计进行了进一步的分析,并给出了系统在673K～1473K内的测温灵敏度。对系统进行优化设计后,在测温范围的低温段,其灵敏度不低于0.5K;在测温范围的高温段,则不低于0.1K。在673K～1473K内,其测温不确定度不低于0.3%。     

多方式温度测量系统

论述了一种多方式温度测量系统的设计,该温度测量系统能够实现PN结、热电阻（PT100）、热电偶（镍铬-镍硅K型）三种方式的温度测量。可以满足不同测量范围、不同测量精度及不同场合的需要。采用EDA与单片机协同设计,并且采用12位模/数转换器,结果表明,不但测量精度得到了极大的提高,而且极高的程序执行速度使得系统响应更快更精确。使得单片机与FPGA的通信成为可能,整个设计理念得到提升。     

热电偶测温系统设计

用热电偶测量温度是航空温度测量中应用最广泛的一种方式,常用来测量高温气流及高速气流。提出了一种可以应用于管道内流体测量的热电偶测温系统的设计方法:以热电偶作为感温元件,配合变换器实现准确可靠的温度测量,输出的电压信号与对应温度成线性关系。通过设计实例及试验,验证了系统的精度性能,实现了预期的设计目标。     

Extended range interrogation of wavelength division multiplexed fibre Bragg grating sensors using arrayed waveguide grating

A technique for interrogating multiplexed fibre Bragg grating (FBG) sensors using an arrayed waveguide grating (AWG) is described. The approach considerably extends the sensing range from that achieved previously, while providing a strain resolution of 17n/spl epsiv///spl radic/Hz at 30 Hz.     

Bend measurement using Bragg gratings in multicore fibre

The first measurements of curvature made using Bragg gratings written in separate cores of a multicore optical fibre are described. The gratings act as independent, but isothermal, strain gauges. The difference in Bragg wavelength between the gratings provides a temperature-independent measurement of the local curvature     

Optical sensor for temperature measurement using bimetallic concept

In this paper, we report an optical fiber sensor for measuring temperature based on bimetallic concept. The sensor is designed by following the basic principle of Fabry–Perot interferometer and theoretical detail of the sensor has been outlined here with a numerical study. An important feature of the proposed sensor is that the fabrication will be done on a commercial multimode optical fiber. The Micro-Electro-Mechanical Systems (MEMS) based fabrication process could be performed directly on a multimode optical fiber end face which will eliminate the need for adhesive in packaging. The sensor could be fabricated as sensor arrays for micro level applications. The potential application of the proposed optical sensor includes biomedical applications, nano research, microfluidics, and other MEMS devices.     

基于混沌的短信数码防伪追溯系统设计

将数码防伪技术和追溯技术相结合,利用混沌信号的特性,研究提出了一种生成防伪追溯二维码的混沌密码加密算法,设计并实现了一套基于混沌的“一键式”短信数码防伪追溯系统,可同时实现商品的真伪鉴别和透明化跟踪溯源,系统测试表明该系统防伪追溯效果好且方便实用,适合推广.