高灵敏度长周期光纤光栅温度传感器的研究

采用纤芯弹光系数大于包层弹光系数的长周期光纤光栅,且在其包层外面涂覆一层随温度升高折射率减小的薄膜材料,同时采用线膨胀系数较大的金属封装光栅等三种增敏措施,可提高长周期光纤光栅温度传感器的灵敏度,测得其灵敏度系数为0.237 5 nm/℃,温度分辨率小于0.1 ℃.     

长周期光纤光栅温度传感器的研究进展

长周期光纤光栅（LPFG）具有与短周期光纤光栅所不同的光谱特性。它无背向反射光谱,不对光源的稳定性产生影响。基于纤芯基模与包层模的谐振耦合原理和热光效应,LPFG温度传感器利用谐振波长的漂移变化实现对温度的测量,具有很高的灵敏度。介绍了LPFG的制作方法、LPFG温度传感器的工作原理及最新研究进展。由于具有插入损耗小、可用于遥测、精度高和抗电磁干扰能力强等优点,LPFG温度传感器将有广阔的应用前景。     

基于级联长周期光纤光栅的新颖温度传感器

设计了一种基于级联长周期光纤光栅(Long period fiber grating)的新颖温度传感器.理论上得到光栅间光纤的长度随温度增加变化时,级联LPG的干涉峰将线性地向长波方向漂移,其消光比亦将呈现线性变化.实验上制作出了基于级联LPG的光纤温度传感器.利用其某一干涉峰的中心波长和消光比测量温度变化时,测量灵敏度分别为0.0353 nm/℃和0.0684 dB/℃.基于级联长周期光纤光栅的温度传感器具有广泛的应用前景.     

基于Ge-As-Se硫系玻璃的高灵敏度光纤光栅温度传感器

采用真空熔融淬冷法制备了Ge₃₃As₁₂ Se₅₅和Ge₂₂As₂₀Se₅₈硫系玻璃,测试结果表明该玻璃在中红外 波段具有宽红外透过范围、高折射率和高折射率温度系数。以此材料为基质,设计了在中红 外波段的硫系 光纤光栅温度传感器。采用传输矩阵法和耦合模方程模拟计算了光纤光栅透射谱和温度传感 特性。研究发 现,设计的光纤光栅温度传感器的中心波长漂移量与温度变化有良好的线性关系。当工作波 长从近红外增 加到中红外波段后,光纤光栅的温度传感灵敏度可以得到极大的提升。计算结果表明,Ge- As-Se硫系布拉 格光纤光栅和长周期光纤光栅在1.55μm的温 度传感灵敏度分别达到了0.123nm/℃ 和0.292nm/℃,是石英基质光纤光栅在该波段的10和 24倍。     

长周期光纤光栅温度传感器应变交叉敏感的研究

长周期光纤光栅是透射谱光栅,纤芯基模与同向各阶包层模发生耦合,谐振波长和幅值对外界环境的变化非常敏感,比传统布拉格光纤光栅具有更好的温度、应力、弯曲、扭曲、横向载荷、折射率等的传感特性.由于长周期光纤光栅对两个或者多个参量都是敏感的,当光纤光栅用于传感测量时,很难分辨出各个参量分别引起的被测量的变化,交叉敏感问题比布拉格光纤光栅严重的多.交叉敏感是光纤光栅传感中的关键问题.分析了目前较为典型的解决策略和方案,在此基础上提出了联系的思想和解决方案,提出并实验验证了一种解决长周期光纤光栅温度传感测量中应力与温度的交叉敏感问题.充分利用了LPFG温度与应变交叉敏感的现象,利用联系的思想,将应变对温度的负面干扰转变为正面的增敏.     

长周期光栅——新兴的光纤光栅传感器

近两、三年来，一类新兴的光纤光栅传感器－长周期光栅型传感器从众多的光栅传感器中脱颖而出。文章重点介绍了ＬＰＧｓ的传感原理、应用及目前发展状况。     

长周期光纤光栅

长周期光纤光栅作为一种重要的光无源器件,与所有光纤传感器一样具有抗电磁干扰、耐腐蚀、灵敏度高、体积小、与光纤系统兼容等优点,在光纤传感与光纤通信领域都有广泛的应用。本文对长周期光纤光栅的模式耦合原理、理论分析方法、光栅制备技术及其在光纤传感与光纤通信领域的主要应用进行了总结分析,其中制备技术主要总结了激光制备技术（包括紫外激光、二氧化碳激光、飞秒激光制备技术）与非激光制备技术（包括电弧放电、机械微弯、包层腐蚀、熔融拉锥、离子注入、超声调制技术）,分别介绍了长周期光纤光栅在温度、应变、弯曲、扭转和环境折射率、生化传感等方面的应用,对于光纤通信领域的应用则侧重于全光纤滤波器、模式转换器、起偏器、模式耦合器等方面。本文是按照教程论文的形式撰写的,旨在为相关领域的学生、科研工作者提供一个系统的介绍。     

倾斜长周期光纤光栅薄膜传感器特性研究

为设计高灵敏光纤光栅薄膜传感器,基于耦合模理论研究了表面镀制高折射率敏感薄膜的倾斜长周期光纤光栅（TLPFG）耦合特性和薄膜折射率传感特性。TLPFG能激发高阶（角向序数l1）包层模耦合,高阶包层模耦合系数随倾角增大而增大,80时,高阶包层模耦合系数远小于1阶包层模耦合系数。研究表明,光栅倾角变化不影响包层模耦合谐振波长,但影响光谱透过率。进一步研究了TLPFG在80时1阶5次包层模耦合的光谱透过率对薄膜折射率变化的响应,分析了光栅结构参数（L、、）和薄膜参数（h3,n3）对薄膜折射率响应灵敏度的影响,结果表明,响应灵敏度相比于非倾斜LPFG可提高一个数量级,对薄膜折射率的分辨率可达10-9。     

高灵敏度液封光纤马赫-曾德干涉仪温度传感器

提出一种结构简单且灵敏度高的液体封装结构光纤马赫-曾德干涉仪(MZI)温度传感器,并对其折射率和温度响应特性进行了理论分析和实验研究。3段单模光纤(SMF)采用锥腰扩大熔接技术顺次熔接构成同轴式光纤MZI,结果表明MZI对环境折射率非常敏感;然后,将MZI封装在充满Cargille液体的毛细管中,结果表明液封后的MZI在测试温度范围内(10~40℃)的灵敏度约150pm/℃,较之封装前提高了1倍,且远高于大多数的光纤光栅和其它光纤干涉仪型温度传感器。本文MZI温度传感器还具有良好的物理强度和易于制备等优点,在环境监测和食品工业等领域具有良好的应用前景。     

基于聚合物微球腔的高灵敏温度传感器（特邀）

提出了一种基于聚合物微球腔的温度传感器,该温度传感器利用微球腔谐振波长漂移量测量外界环境温度变化量,兼具结构紧凑和高度灵敏的特点。首先利用有限时域差分法对拉锥光纤耦合聚甲基丙烯酸甲酯(PMMA)微球的谐振结构进行了仿真分析,验证了拉锥光纤激发聚合物微球腔中回音壁模式的可行性。实验结果表明,束腰直径为1.8 μm的拉锥光纤与直径为数十微米的聚合物微球之间通过消逝场耦合的方式能够激发品质因子为104量级的回音壁模式。利用点式封装和全包裹封装相结合的方式将拉锥光纤和聚合物微球封装一体,一方面可保持两者之间稳定的耦合状态,另一方面保护拉锥光纤和微球腔免受外界污染。由于聚合物微球腔的负热光系数大于其热膨胀系数,其谐振光谱随外界温度降低发生红移。当外界环境温度在20~30 ℃范围内变化时,聚合物微球腔温度灵敏度为68 pm/℃。与传统光纤温度传感器相比,该传感器的高品质因子使其具有更低的探测极限,在受限空间内的原位温度精密测量中具有潜在的应用前景。     

Highly sensitive Hall magnetic sensor microsystem in CMOStechnology

A highly sensitive magnetic sensor microsystem based on a Hall device is presented. This microsystem consists of a Hall device improved by an integrated magnetic concentrator and new circuit architecture for the signal processing. It provides an amplification of the sensor signal with a resolution better than 30 μV and a periodic offset cancellation while the output of the microsystem is available in continuous time. This microsystem features an overall magnetic gain of 420 V/T     

Highly sensitive electrostatic voltage sensor on SAW double-waveguides

An electrostatic voltage sensor using two SAW oscillators based on SAW Delta v/v waveguides was constructed. The frequency difference between these two oscillators is proportional to the electrostatic voltage applied between the waveguides and special planar electrodes. The steepness of voltage-frequency characteristic as high as 1.32 kHz/V was obtained that provided a very high sensitivity, several orders of magnitude higher than in all SAW voltage sensors reported previously.<>     

基于磁光波导的液体折射率传感特性研究

为了对溶液折射率进行精确测量和传感,采用转移矩阵法对Ce:YIG/Ag/liquid 3层基于磁光表面等离子共振的结构与棱镜组成耦合系统进行了数值计算,并用有限元法进行了模拟仿真。由低损耗的Ag和强磁光性的Ce:YIG组成的结构在入射光波长为980nm时,灵敏度达到4.082/RIU（溶液折射率n=1.330~1.340）。结果表明,与其它传统的表面等离子共振传感结构相比,本文中提出的折射率传感器的灵敏度大大提高。该结构在实际应用中可以更加简便地探测溶液的折射率。     

Highly sensitive optical hydrogen sensor using circular Pd-coatedsinglemode tapered fibre

A novel optical hydrogen sensor, based on the absorption change of the evanescent fields in a circular Pd-coated singlemode tapered fibre is presented. The proposed sensor is polarisation independent and its sensitivity is adjustable by means of the taper diameter, interaction length, and/or light wavelength. A simple light transmission measurement setup is used to test the sensor. The sensor is suitable for the detection of low hydrogen concentrations with high sensitivity and fast time response. Transmission changes as high as 60% are demonstrated     

Highly sensitive field effect charge sensor for direct detection of biomolecules

A field effect transistor (FET) charge sensor is proposed to work at a special operating condition in order to become extremely sensitive to the gate charge change caused by biomolecules. A device model has been established and the simulation results justify the hypothesis. It is found that at the depletion operating condition the proposed FET charge sensor will shift a gate voltage up to 1 mV in response to every electron per square micron, which is much more sensitive than other existing FET sensors.     

Highly sensitive twist sensor based on tilted fiber Bragg grating of polarization-dependent properties

The transmission intensity of the tilted fiber Bragg grating (TFBG) is strongly dependent on the polarization properties of the TFBG. The polarization characteristic of the cladding modes can be used for twist measuring. In this paper, a highly sensitive fiber twist sensor is proposed. The transmission intensity on the strong loss wavelength showed a quasi-sin θ changing with the twist angle ranging from 0° to 180° for S- or P-polarized input. A high sensitivity of 0.299 dB/° is achieved, which is almost 17.9 times higher than that of the current similar existing twist sensor. The twist angle can be measured precisely with the matrix.     

一种基于LPG的高灵敏度折射率传感器

报道了一种高灵敏折射率传感器.该传感器采用2个具有相似透射谱(3 dB透射深度)的长周期光纤光栅(LPG)组成光纤型Mach-Zehnder(M-Z)干涉仪,通过减小两LPG之间的光纤包层直径,以增强包层中的传输模在环境中的倏逝场,从而提高对环境折射率测量的灵敏度.实验结果表明,该折射率传感器比常规的LPG对构成的传感器能有效的提高灵敏度4倍左右.     

Highly sensitive submillimeter InSb photodetectors

Submillimeter photoconductivity of the electron gas in bulk InSb has been studied. A new design of the InSb photodetector in the form of planar coils with a length-to-width ratio of two orders of magnitude is suggested. This design enables fabrication of highly sensitive photodetectors with the responsivity peak tunable by magnetic field.