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对于涂覆长周期光纤光栅(LPG)传感元件,涂覆层折射率大于包层折射率时将具有很高的灵敏度.然而在涂覆层厚度为纳米量级时,涂覆层的折射率将具有一定的吸收,吸收将对LPG传感元件产生一定的影响.本文在线偏振(LP)模近似理论和耦合模理论(CMT)的理论模型基础上,通过数值计算对这一情况进行研究讨论.详细分析了模式转变点附近和远离模式转变点区域涂覆LPG的模式结构和透射谱情况.在无吸收的理想模型基础上,详细分析了消光系数对模式转变和重新组合的影响,以及模式结构的转变对LPG透射谱的影响,得出吸收将会导致LPG灵敏度、可测量的动态范围的变化.最后,文章给出了一种新型的LPG吸收传感元件的模型. 相似文献
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级联长周期光纤光栅的谐振峰对外界折射率较敏感,利用该特性制成的折射率传感器可以实现对溶液折射率和浓度的实时在线测量。通过对不同折射率的NaCl溶液和蔗糖溶液的实验研究,得出溶液折射率、浓度与谐振峰之间的关系。实验结果表明: LPGP较为灵敏的外界折射率范围为1~1.4513,在此范围内,随着外界折射率的增加,透射谱干涉峰的幅值逐渐减小而谐振波长逐渐向短波方向漂移。该传感器可应用于生物、化学、过程控制等高灵敏度传感领域的各种溶液进行监控,具有较高的实用价值。 相似文献
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《中国计量学院学报》2015,(2):156-160
针对当前橄榄油掺假问题,提出一种测定橄榄油纯度的新方法.将纯橄榄油和纯葵花籽油按不同比例配置得到不同纯度的待测橄榄油,用阿贝折射计测出各样品的折射率,得到样品纯度与折射率之间的线性关系.利用长周期光纤光栅传感器对外界折射率的敏感性特性,将不同纯度的待测橄榄油分别滴加到长周期光纤光栅表面;宽带光源发出的光经过其表面进入光谱仪后得到不同纯度样品的透射谱.实验测得不同纯度的橄榄油样品与衰减峰的强度变化存在线性关系,灵敏度为0.007 04dB/%,线性度较好,决定系数R2约为0.96.根据光谱仪的强度分辨率可以计算得到橄榄油纯度的探测极限为1.42%.研究结果表明,利用该长周期光纤光栅传感器可以简单、快捷、准确地测定橄榄油的纯度,具有一定的应用价值和前景. 相似文献
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光纤布拉格光栅(FBG)传感器最常用的封装材料是环氧树脂粘合剂,容易老化和失效,会影响传感器的性能和寿命。该文采用一种新型光纤光栅压力传感器,比较厚度分别为2.0 mm、3.0 mm、3.5mm及4.0 mm的6061 T6铝合金承压面对新型光纤光栅压力传感器标定的影响。由试验结果可知,新型光纤光栅土压力传感器承压面厚度为2.0 mm的标定结果最差,拟合线性度为0.991 94,传感器重复性较差;承压面厚度为3.5 mm的标定结果最好,拟合线性度为0.999 77,重复性最好且传感器灵敏度误差较小。该研究结果可以为后续新型光纤光栅压力传感器的生产设计提供参考。 相似文献
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改进型双光栅矩阵运算光纤光栅传感器 总被引:4,自引:1,他引:3
在光纤光栅传感器的应用中一直存在着交叉敏感问题,必须采取各种措施进行补偿或区分。 在悬臂梁的上下两面分别粘贴光纤光栅,通过分别测量这两个光栅的波长位移的改进型双光栅矩阵运算法来克服交叉敏感问题。该方法只需要一套光源和检测系统,装置简单,具有较低的成本和实际应用前景。 相似文献
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介绍了封装对光纤光栅纤内谐振腔的光学特性的影响、基于压力增敏的先纤光栅封装的物理机制及其研究进展。综述了解决应变和温度交叉敏感问题的方法,提出了一种基于压力传感增敏效果好的多层封装结构,同时还利用2种聚合物不同的力学特性,设计了一种解决应变和温度交叉敏感的封装方法,讨论了封装材料对增敏效果的影响. 相似文献
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带温度补偿基于薄壁圆筒结构的光纤光栅压力传感器 总被引:2,自引:0,他引:2
阐述了一种带温度补偿、基于薄壁圆筒结构的高量程光纤光栅(FBG)压力传感器.薄壁圆筒直接作为弹性体,在压力作用下产生轴向位移来拉动压力敏感光纤以实现压力传感;通过被动温度补偿和残留温度效应主动实时修正来共同消除薄壁圆筒和压力敏感FBG的温度漂移;同时,对带温度补偿的FBG压力传感器的温度稳定性进行了讨论,给出了理想情况下该系统可达到的最优温度稳定性及决定因素.研究结果表明:基于30CrMiSiA材料管道结构的FBG压力传感器可以进行压力传感,其重复性为0.505 2%;回程误差为4.006%;线性度为0.285 5%;传感器精度为±2.639 8%;基于温度补偿进行温度去敏也有很好的效果,在-30~100℃范围内,该系统的温度稳定性因子为9.079 6%;随着实验温度范围减小至0~60℃,系统温度稳定性因子也减小至4.0%. 相似文献
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张晓春 《中国新技术新产品》2012,(10):28-29
光纤光栅传感系统使用光纤作为测量元件和信号传输介质,为提高光纤对温度、应力的敏感程度及准确定位能力。文章对光纤光栅传感系统的基础知识、系统维护、制作原理及使用注意事项进行了简要的论述。 相似文献
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A superimposed long period fiber grating design proposed for refractive index sensing is shown to be superior to conventional dual resonance and turnaround point gratings and can operate at any chosen wavelength region by appropriate design. Numerical simulations carried out on standard single mode fibers show that such sensors can operate over a wide refractive index range (1.33–1.42) exhibiting a high sensitivity of ~500–1545?nm/RIU, yielding ~10?6–10?7 refractive index change corresponding to the resonance relative shift of 1?pm with potential applications to chemical and biological industries. The proposed scheme can also discriminate between refractive index and temperature changes. 相似文献
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A novel torsion sensor is proposed, which is composed of one long period fibre grating and one asymmetrically corrugated long period fibre grating based on the high-frequency CO2 laser pulses technology and burning fibre coating and etching cladding technology, respectively. By combing the advantages of the two aforementioned elements, a sensitivity of 331.7 and 310.3 pm/(rad/m) towards clockwise and anticlockwise direction, respectively, is reached in the experiments. 相似文献
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A magnetic field sensor based on a magnetic fluid (MF)-coated intermodal interferometer is proposed and experimentally demonstrated. It is fabricated by a core-offset structure between two segments of multi-mode fibres (MMF), a spherical structure is formed in the end of the second segment MMF. The core-offset section can be used to excite the core mode to the cladding, then the core and cladding modes will interference at the spherical structure due to the optical path difference caused by the refractive index difference. Two interference valleys of the interferometer integrated with MF under different magnetic field intensities have been experimentally analysed. The experimental results exhibit that the sensor possesses a magnetic field sensitivity of ?0.187 nm/mT by monitoring the wavelength shift at the magnetic field intensity from 0 to 20mT, and the optical power attenuation at specific wavelength with a magnetic field has a maximum sensitivity of 0.228 dB/mT. 相似文献
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A kind of compact fibre-optic sensor based on no-core fibre (NCF) cascaded with a strong coupling long-period fibre grating (LPFG) is proposed and experimentally demonstrated. The sensing mechanism is based on the Mach–Zehnder-like interference between the core fundamental mode and cladding mode of the fibre structure. The NCF and LPFG are used as the mode exciter and combiner, respectively. Due to the particular properties of the strong coupling LPFG, the measurements of refractive index (RI) and temperature with high sensitivity are realized by monitoring the transmission spectrum with intensity and wavelength interrogation techniques, respectively. The achieved RI sensitivity reaches ?580.269 dB/RIU in the range of 1.436–1.454 and the temperature sensitivity reaches 27.2 pm/°C. 相似文献
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Hydrogen sensor based on side-polished fiber Bragg gratings coated with thin palladium film 总被引:1,自引:0,他引:1
A new type of hydrogen sensor based on a side-polished fiber Bragg grating (FBG) coated with thin palladium film was demonstrated experimentally. The used FBG with the reflectivity of 90% is fabricated in a hydrogen-loaded single-mode fiber (SMF-28) by using the phase mask writing technique of a KrF excimer laser. The experimental results show that proposed sensor can be applied for hydrogen concentration measurements. 相似文献
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一种用于低频测量的光纤光栅振动传感器 总被引:1,自引:1,他引:1
利用光纤光栅敏感技术,设计了一种用于低频测量的光纤光栅振动传感器.该传感器采用了等强度悬臂梁作为振动传感元件,并在等强度悬臂梁的上下双面优化布置性能匹配的两个光纤光栅,一个为振动敏感测量光栅,另一个为信号匹配滤波解调光栅.该结构设计可以补偿温度的不利影响,同时也提高了传感器信号检测的灵敏度.实测结果表明,该传感器可以用于25 Hz以下的低频目标的振动测量. 相似文献
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An optical fiber humidity sensor was fabricated using a hydrophilic gel (agarose) deposited on the tapered plastic optical fiber (POF). The sensing element, agarose, can absorb and exude moisture from/to the ambience, thereby altering its refractive index and changing its ability to modulate the intensity of light that propagates through the fiber. Thus, the operating principle of the sensor is based on the intensity modulation technique, which utilizes a tapered POF probe coated with agarose that is sensitive to humidity. The POF, which was fabricated using an etching method, has a waist diameter of 0.45 mm and tapering length of 10 mm. As the relative humidity varies from 50% to 80%, the output voltage of the sensor with agarose gel of 0.5% weight content decreases linearly from 2.24 mV to 1.55 mV. The agarose-based sensor produces a sensitivity of 0.0228 mV/%, with a slope linearity of more than 98.36%. The tapered fiber with agarose gel of 1% weight content produces a sensitivity of 0.0103 mV/% with a slope linearity of more than 94.95% and a limit of detection of 2.635%, while the tapered fiber with agarose gel of 1.5% weight content produces a sensitivity of 0.0079 mV/% with a slope linearity of more than 98.53% and a limit of detection of 6.853%. The fiber with agarose gel of 0.5% weight content shows higher sensitivity compared to that of 1% and 1.5% due to the effect of pore size, which changes with concentration. The results demonstrate that agarose-based optical fiber sensors are both sensitive and efficient for economical and flexible measurements of humidity. 相似文献
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We report on recent experimental results obtained with fiber Bragg grating (FBG) microphone for acoustic measurement. The sensing element is formed by longitudinally sticking ends of two FBGs onto a titanium film, and then being packaged in an aluminum cylinder. Due to wavelength shift of the FBGs induced by the external acoustic disturbance, the corresponding periodic fluctuation in power can be observed on the optical oscilloscope. Theoretical analysis verifies that the optical power variation, result of the titanium film vibration caused by the acoustic disturbance, possesses a linear relationship with the sound pressure in a specific range. A relatively flat frequency response in the range from 100?Hz to 1?kHz with the average signal-to-noise ratio (SNR) above 22?dB is experimentally demonstrated. The maximum sound pressure sensitivity of the proposed sensor is found to be 90?μW/Pa within a sound pressure range 100.3–118.5?dB. The sensing system presents good stability and reliability, and has the advantage of direct self-demodulation. 相似文献