基于倾斜光纤光栅的相对湿度传感器

提出了一种基于倾斜光纤光栅(TFBG)的包层上覆盖着聚乙烯醇(PVA)的空气相对湿度传感器,成功实现了对相对湿度在20～98%RH范围内的监测。研究发现,TFBG的透射功率在20～74%RH和74～98%RH2个相对湿度区域内分别呈现不同的线性变化,敏感度分别为2.52 dBm/%RH和14.95 dBm/%RH,并且在高湿度区有更高的敏感性。     

基于PI湿敏薄膜的分布式光纤Bragg光栅湿度传感器

研究了基于聚酰亚胺（PI）湿敏薄膜的分布式光纤Bragg光栅（FBG）湿度传感器。传感器利用PI薄膜湿膨胀效应,将湿应变作用于Bragg栅区,从而改变光纤FBG湿度传感器中心波长的原理,实现了对26-98％RH范围内环境相对湿度的监测。通过改进PI湿敏薄膜的制备及涂覆工艺,有效提高了FBG湿度传感器性能,并采取了相应温...     

用于PEMFC的FBG湿度传感器的制作及性能研究

研究了以聚酰亚胺为湿敏材料的光纤Bragg光栅(FBG)湿度传感器并用其对质子交换膜燃料电池(PEMFC)停机过程中内部湿度进行了实时监测。传感器利用聚酰亚胺的湿膨胀效应,实现 了对24.7%－ 98%RH范围内相对湿度的监测。采用腐蚀光纤包层的方法减小光纤包 层直径,实验结果表明,该方法能在 不影响FBG相对湿度传感器灵敏度的情况下,提高对外界环境相对湿 度变化的响应速度。所 研制的FBG 相对湿度传感器灵敏度能达到3.8 pm/RH,线性度达到99.85%,最大回程误差不超过9pm,当环境相对湿 度从50%突变到85%时,经过腐蚀处理后的FBG 相对湿度响应时间仅为15.4 s。将该FBG湿度传感器布置 于PEMFC内部进行停机过程中湿度的实时监测,实验结果表明,所制作的FBG湿度传感器能够 准确地反映PEMFC停机吹扫过程中内部湿度的变化。     

基于光纤环镜的温度不敏感相对湿度传感器

提出了一种基于两段相同长度的保偏光纤环镜的温度不敏感相对湿度传感器,其中一段保偏光纤经高浓度的氢氟酸腐蚀后覆以一层湿敏材料聚乙烯醇薄膜用于获得空气的相对湿度,另一段保偏光纤则对传感器的温度进行补偿。该传感器成功实现了对周围环境相对湿度(RH)20%~80%范围内的测量,同时不受外界环境温度的影响。实验表明,该传感器所得数据呈现出良好的线性关系,获得的湿度灵敏度为0.98 nm/%(RH),温度所带来的影响仅为0.0072 nm/℃,达到了消除温度影响的目的。     

U-shaped micro-groove fiber based on femtosecond laser processing for humidity sensing

A novel optical fiber sensor with a U-shaped micro-groove structure ablated by femtosecond laser on single-mode fiber for measuring air relative humidity (RH) is reported in this paper. In order to improve the accuracy of sensor, a graphene oxide (GO)/polyvinyl alcohol (PVA) composite film is coated on the surface of micro-groove structure. In the U-shaped micro-groove structure, the remaining core and micro-cavity in the micro-groove make up two major optical propagation paths, forming a Mach-Zehnder interferometer (MZI). The sensor has a good linear response within the RH range of 30%—85%, and the maximum sensitivity can reach 0.638 1 nm/%RH. The effect of temperature on the overall performance of the humidity sensor is also investigated. As a new type of all-fiber device, the sensor shows excellent sensitivity and stability.     

基于差压原理的矿用光纤光栅风速传感器

设计了一种新型的矿用光纤光栅风速传感器,利用差压原理实现风速转化,由波纹管、等强度悬臂梁和双光纤光栅组成差分敏感机构,并通过算法进一步进行温度补偿,有效克服了温度交叉敏感问题,提高了应变测量的灵敏度。文中推导了光纤光栅中心波长变化量与风速的关系,同时对敏感机构进行了水压模拟试验,得到传感器敏感机构的灵敏度为0.703 pm/Pa,与理论值具有很好的吻合度;对风速传感器样机进行风洞试验测试,结果表明风速在0.2~20 m/s的情况下,传感器测量误差可基本控制在0.3 m/s以内,并具有良好的线性关系。     

Relative Humidity Sensor Based on Tilted Fiber Bragg Grating With Polyvinyl Alcohol Coating

A relative humidity (RH) sensor based on tilted fiber Bragg grating (TFBG) is proposed by utilizing polyvinyl alcohol (PVA) as the sensitive cladding film. RH increasing in the PVA coating will result in reduction of refractive index. Due to the TFBG's sensitivity to ambient refractive index, the spectral properties of PVA-coated TFBG are modified under exposure to different ambient humidity levels ranging from 20% to 98% RH. The transmission power of TFBG has different linear behaviors for two different humidity ranges (20%–74% RH and 74%–98% RH), and the sensitivity for each humidity range reaches as high as 2.52 and 14.947 dBm/%RH, respectively. Combining the advantages of optical fiber grating and PVA as a smart material, this design involves simple configuration, low cost, compactness, a small degree of hysteresis, stability, and wide dynamic sensing range as well. Therefore, the sensor could be applied in real-time RH monitoring for normal as well as extremely humid environments.      

PCF-multimode/endless fiber sensor for respiratory rate monitoring

A respiratory monitoring system was proposed based on optical fiber. The sensor consists of photonic crystal fiber (PCF) spliced with multimode fiber (MMF) to fabricate Michelson interferometer. The sensor is inserted into an oxygen mask tube and then put on the nose and mouth to monitor the respiratory rate (RR) for different cases. The results showed that when breathing increased, the intensity of light decreased. The intensity of light in the sleeping case of breathing was more intense than that when the intensity of working sport was measured. The working sport case was a higher transmittance than that of sleeping. The sensitivity of the sensor was also measured to be 231.9 pm/RH.     

A high-speed capacitive humidity sensor with on-chip thermal reset

This paper reports a high-speed capacitive humidity sensor integrated on a polysilicon heater. A response time of 1.0 s and a sensitivity of 30.0 fF/%RH have been obtained. High speed is achieved using multiple polyimide columns having diameters of a few microns and allowing moisture to diffuse into them circumferentially. Using structures that eliminate the air-gap capacitance between the columns, the simulated sensor output drifts by only 1% when the relative dielectric constant in the air region changes from 1 to 10. A polysilicon heater is used to measure relative humidity levels >80% RH. An accuracy of ±3% RH has been obtained using this method, with measurement errors of ±0.5°C and ±2% RH in temperature and relative humidity, respectively. The heater also reduces the recovery time after wetting, enables the sensor to recover from contamination and aging, and allows the sensing film to be reset on demand during self-test protocols     

基于光纤光栅的杆型二维振动传感器

为了实现两个方向的振动信号检测,提出了一种以杆为弹性结构的二维光纤光栅振动传感器。首先对该传感器进行了理论分析,并推导出其固有频率和灵敏度公式。然后对传感器结构进行了优化仿真,确定各个参数的最终值。最后通过实验研究了传感器的各项性能。实验结果表明,该传感器在x方向上的固有频率为493 Hz,灵敏度为54 pm/g,线性度为99.9%;在y方向上的固有频率为466 Hz,灵敏度为5 pm/g,线性度为97.5%。此外,采用双光纤光栅消除了温度对振动信号测量的影响,温度灵敏度为0.1 pm/°C。该传感器结构简单,可检测两个方向的振动信号,消除了温度的影响,在振动信号检测中表现良好,因此在多维振动信号检测领域具有重要研究意义。     

一种基于柔性铰链的FBG加速度传感器

为了适应光纤传感器在采煤机中的应用,提出了一种基于柔性铰链的光纤布拉格光栅(FBG)加速度传感器,其质量块通过柔性铰链和基座连接。基于传感器的结构模型,从理论给出了传感器的灵敏度和谐振频率公式,并讨论了结构参数对传感器灵敏度和谐振频率的影响,还利用有限元法分析了传感器的静态和动态特性。实验表明,本文传感器的谐振频率为2kHz,峰-峰值灵敏度为22pm/g,横向抗干扰度小于10%,适用于1kHz以下加速度的测量。     

基于柔性铰链结构的高灵敏度低频光纤光栅加速度传感器

设计了一种基于柔性铰链结构的光纤光栅加速度传感器,进行了结构理论分析,并构建有限元模型仿真分析了传感器的加速度传感特性。基于F-P滤波器构建了具有温度自补偿功能的光纤光栅加速度检测系统,并通过增加反馈控制电路,对F-P滤波器进行反馈控制,实现了系统的零点自温度补偿。对系统的特性进行了实验测试,结果表明:系统对加速度的连续激励信号和冲击激励信号均有良好的动态响应,系统的固有频率为380.0 Hz,动态响应范围可达65.6 dB,频率响应范围为10.0 ~240.0 Hz,灵敏度为236 pm/g,所设计的加速度传感器具有较强的横向抗扰能力,干扰方向灵敏度仅为工作方向灵敏度的3.5%。     

SnO_2-LiZnVO_4系湿敏元件电容特性分析

采用共沉淀法制备SnO2-LiZnVO4系湿敏材料,研究了LiZnVO4的掺杂量对材料湿敏电容的影响。结果表明:LiZnVO4的掺杂量,环境的相对湿度(RH)、测试信号频率对湿敏电容有较大影响。当x(LiZnVO4)为10%时,可使材料具有合适的低湿电容和灵敏度。在100Hz下,当环境的RH从33%上升到93%时,SnO2-LiZnVO4系湿敏材料制备的湿敏元件的电容增量可达起始值的2300%,显示出较高的电容湿度敏感性。湿敏元件的电容响应时间约为54s,恢复时间约为60s。湿滞约为RH6%。     

复合钒钛酸干凝胶薄膜的湿敏特性研究

采用sol-gel法制备了复合钒钛酸干凝胶(H2V10Ti2O30-y·nH2O)薄膜,并对其湿敏特性进行了研究。结果表明:该薄膜为层状结构。用此薄膜制备的湿敏元件,在RH为11%～95%的范围内,感湿特性曲线线性好,其响应、恢复时间分别为5s和20s,湿滞为RH2%,感湿温度系数为RH0.45%/℃,并具有良好的稳定性。H2V10Ti2O30-y·nH2O干凝胶薄膜湿敏元件的灵敏度和湿滞均优于复合钒酸(H2V12O31-y·nH2O)干凝胶薄膜湿敏元件。     

井下油套环空级联式光纤光栅压力传感器的研制

为了实现对油水井下油套环空中狭小空间大量程压力的监测,研制一种级联式的光纤光栅压力传感器。首先,根据实际工况,设计一种基于平膜片和等强度梁相结合的光纤光栅压力传感器封装结构;采用级联式的方法,在未改变原有光纤光栅性能指标的前提下,扩大传感器的测量范围,解决压力测量范围和灵敏度之间的矛盾;通过力学分析验证研制的传感器结构的合理性与可行性,同时阐明其温度补偿的方法。实验结果表明:本文传感器的测压范围为0～30MPa,灵敏度为329.5pm/MPa,线性度达到98%以上。并且传感器结构简单,尺寸小巧,易于实现,装配到油管后的实际厚度仅为17mm,能够满足油水井下油套环空中压力的监测要求。     

一种拉杆式的光纤光栅应变传感器

提出了一种拉杆式的光纤光栅应变传感器,并进行了理论分析和传感器标定实验研究。传感器由悬臂梁组成弹性系统,将光纤粘贴于悬臂梁内锥形孔内,利用拉杆传递监测对象表面应变变化。实验结果表明,传感器的应变灵敏度为1pm/με,线性度为0.994;温度灵敏度为16pm/℃,线性度为0.996。可应用于高精度要求下的应变测量。     

光纤光栅原油压力传感器实验及其可靠性研究

介绍并制作了一种光纤光栅高温高压传感器,它由三种金属管组成,中央的弹性金属管将液体的压力转换为管子的机械伸长,周围金属管的长度只随温度变化。光纤光栅的两端分别固定在中央管及周围管的末端,随着压力管内液体压力的增加,光栅的中心波长随之增加,实现了对液压的传感。对该传感器的温度补偿进行了分析,设计了具有相同温度系数的压力传感光栅与温度传感光栅。并对传感器进行了高压实验和高温、高湿存储实验。结果表明,这种压力传感器在0~50 MPa之间灵敏度为31.7 pm/MPa。经过200℃高温存储16 h,及100℃沸水浸泡6 h,波长没有观察到明显衰退现象。     

Novel capacitance-type humidity sensor based on multi-wall carbon nanotube/SiO2 composite films

A novel capacitance-type relative humidity (RH) sensor based on multi-wall carbon nanotubc/SiO2 (MWCNTs/SiO2) composite film is reported.Details of the fabrication process,possible sensing mechanism and sensing characteristics,such as linearity and sensitivity,are described.The capacitance of the MWCNTs/SiO2 composite film shows typical concentration percolation behavior with increasing MWCNT loading.At loadings below the percolation threshold (1.842wt％),the sensor capacitance increases obviously with increasing MWCNTs.The water condensed in the MWCNTs/SiO2 layer can lower the percolation threshold and increase the sensor capacitance.The sensor with MWCNT concentration of 1 wt％ has the best properties.The sensor has a humidity sensitivity of about 673 pF/％ RH and a linearity correlation of 0.98428.The response time of the sensor to RH is about 40 s and the recovery time is about 2 s.     

基于磁流包覆冷却拉锥全光纤磁场传感器特性研究

为提高光纤传感器磁场检测中的敏感度,进一步实现弱磁场环境中的高精度场强勘测,提出一种基于磁流包覆与冷却拉锥透射式全光纤高灵敏磁场传感器,拉锥过程采用间歇式停顿冷却技术,可更加便捷获得高质量干涉谱,减缓光子晶体光纤空气孔塌缩,制作工艺简单,具有可操纵性强、灵敏度高、损耗小等优势,实现了高灵敏磁场环境实时在线检测,并对传感器的变温影响进行了讨论。实验结果表明,光子晶体光纤的拉锥长度为5.5mm、腰椎直径为75μm时,可得到良好的干涉光谱,在0~78 Oe(1 Oe■79.578A·m-1)磁场范围内,灵敏度达95pm/Oe,线性拟合度为98.31%。     

车载直接探测多普勒测风激光雷达光学鉴频器

基于建立的车载直接探测激光雷达系统,对接收光学鉴频器进行了研究。针对边界层、对流层和平流层不同的气溶胶和大气分子浓度以及风速动态范围,同时采用直接探测的两种主要技术。利用多光束菲索(Fizeau)干涉仪(MFI)和阵列光电倍增管(PMT),接收气溶胶散射信号,获得边界层风速。采用双法布里-珀罗(Fabry-Perot)干涉仪(DFP)和光电倍增管探测器,分析分子散射信号,得到对流层风场。使用实际的激光雷达系统参数和大气模型参数,对两个鉴频器进行了优化设计,分析了它们的风速测量灵敏度和精度。多光束菲索干涉仪鉴频器系统在±50 m/s风速范围内测量灵敏度为1.3%/(m.s-1),高度分辨率为200 m,边界层内风速测量误差小于1 m/s。双法布里-珀罗干涉仪鉴频器系统在±100 m/s风速范围内的测量灵敏度约为0.3%/(m.s-1),高度分辨率为1000 m,对流层风速测量误差小于3 m/s。