光纤压力传感器的理论与实验研究

本文论述了一种光纤传感器的理论和实验结果,用单模光纤作为Mach-Zehnder干涉仪的两臂,在光源相干长度内、两臂光程几乎相等时,则两臂的光相遇时形成一系列干涉条纹。当两根光纤受到不同压力时,两束光就发生相对相位变化,从而干涉条纹的花样产生位移.本实验就是通过测量这种位移来确定光纤所受的压力。这样就可以将本装置作为压力传感器.     

一种新型光纤光栅F-P电流传感器系统

基于磁致伸缩效应和F-P干涉原理,对传统内腔式光纤F-P传感器进行了改进,通过在一根单模光纤上制作两个参数完全相同的光纤布拉格光栅(FBG),作为F-P腔的两个反射面,设计出一种新型光纤电流传感器.与传统的基于F-P干涉仪原理的光纤传感器相比,该传感器不再将光强作为直接测量值,而是通过测量光强变化频率(数字量)实现对电流强度的测量,避免了直接测量模拟信号带来的较大误差,使传感器具有较强的抗干扰能力和稳定性.首先分析了该传感器的工作原理,然后给出了传感器系统的设计方案,最后用实验进行了验证,当交流电流在0～3 A变化时,实验数据与理论计算的结果相当吻合.     

动态压力光子晶体光纤传感器的研究

光子晶体光纤传感器可广泛用于各种动态压力测量中.文章设计了一种动态压力光子晶体光纤传感器,采用差分平衡方法分析了这种传感器的压力作用原理,讨论了这种传感器的输出信号检测方案,结果表明,该传感器对外界压力作用的响应具有周期性,响应周期与外界压力和传感器敏感元件长度相关.     

塑料光纤泄漏传感器的设计和性能

介绍了一种塑料光纤（POF）传感器的设计和操作，该传感器以从一根光纤到另一根光纤产生强度调制的非常规光泄漏为基础。人们已发现，主要损耗机理是渐逝损耗，并基于此现象设计出该光纤传感器。计算渐逝波的有效肤深与不同包层折射率之间的关系。将这种传感器作为不同液体的液位传感器，对其进行了试验并比较了试验结果。测量了用于这种探头的一系列测量的干输出（空气界面层）和湿输出（液体界面层）信号，并叙述了涉及传感器工作的重要因素。此外还报道了测量值的精度、结果的再现性（误差1.35％）和传感器工作的稳定性与不同入射功率下的时间之间的关系（误差0．85％）。报道的这种设计具有应用前景，并证实了这种器件作为液位探头以及双位开关的成功运行。     

光纡压力传感器探头的设计

介绍了一种光纤压力传感器探头的设计和计算。利用平膜片实现压力与位移的转换,其位移由光纤传感器检测出来。探头中两光纤呈θ角度放置,能使系统的灵敏度达到41.6mV/MPa。传感器探头的最大承压为3mPa。     

C型弹簧管光纤压力传感器

本文介绍了一种用Ｃ型弹簧管作为压力敏感元件，采用双面反射进行强度调制的光纤传感原理，实现压力检测。这种传感器可以充分利用光纤的接收特性，有效地解决动态范围与灵敏度成反比的矛盾，并能够消除光源强度变化以及其它因素对测量带来的影响。     

微小型高压力流体电磁控制阀

用于航空航天领域微流量控制系统中的微小型阀,需要具有耐高压、低泄漏、高频响和高控制精度等综合性能。本文提出了一种可控高压力微流体的常闭微小型阀的设计方案用于满足该系统需要,其特点在于采用以较小的致动力控制较高的流体压力的结构原理,并以弹性材料薄膜作为阀芯的支承结构件同时作为密封件。该阀由其本体结构和外置致动器两部分构成,其本体结构的设计在制作工艺上适合进一步的微小型化,外置致动器的设计具有较大灵活性。初步研制了采用电磁致动的小型常闭阀样机既可控气体又可控液体的特性。实验测试其工作压力范围为0～5atm,阀的驱动响应时间小于5ms,流量控制分辨率达到9μL／pulse,无泄露。     

微小型高压力流体电磁控制阀

用于航空航天领域微流量控制系统中的微小型阀 ,需要具有耐高压、低泄漏、高频响和高控制精度等综合性能。本文提出了一种可控高压力微流体的常闭微小型阀的设计方案用于满足该系统需要 ,其特点在于采用以较小的致动力控制较高的流体压力的结构原理 ,并以弹性材料薄膜作为阀芯的支承结构件同时作为密封件。该阀由其本体结构和外置致动器两部分构成 ,其本体结构的设计在制作工艺上适合进一步的微小型化 ,外置致动器的设计具有较大灵活性。初步研制了采用电磁致动的小型常闭阀样机既可控气体又可控液体的特性。实验测试其工作压力范围为 0～5atm ,阀的驱动响应时间小于 5ms,流量控制分辨率达到 9μL/ pulse ,无泄露     

用于流体压力测量的电容传感器

叙述了电容应变式流体压力传感器的基本原理，给出了一种电容应变式流体压力传感器的检测电路，并分析了流体压力大小与传感器输出电压的关系。实验结果表明，该传感器具有精度高、线性度好、灵敏度大等优点，尤其适于微压力和大动态力的测量。     

一种基于激光自混合干涉的光纤压力传感器

文中理论和实验研究了一种基于激光自混和干涉技术的光纤压力传感器,阐述了其设计理论和实现方法,建立了光纤压力传感器模型,实验研究了应力与激光自混和干涉输出的对应关系;实验结果表明所设计的光纤压力传感器的原理是正确和可行的.     

Universal fiber-optic point sensor system for quasi-static absolutemeasurements of multiparameters exploiting low coherence interrogation

A universal fiber-optic high-resolution point sensor system, based upon signal recovery by dual-wavelength low coherence interferometry, has been developed and demonstrated for quasistatic absolute measurements of multiparameters. This system is capable of multiplexing up to 32 fiber-optic point sensors which can be fiber optic interferometers or fiber Bragg gratings or any combination of the two. The topology of this system is based on a spatially multiplexed scheme with low coherence signal recovery that we have reported previously. A range of multiparameter point sensors, including a medium pressure sensor, a high pressure sensor, a miniature temperature sensor, a displacement sensor, and a fiber Bragg grating strain sensor with drift-compensation, have been developed and incorporated into this network and demonstrated A range to resolution of better than 10⁴ :1 and 2×10³:1 has been achieved for the interferometric sensors and the Bragg grating strain sensor, respectively. The interchangeability of the sensors has also been demonstrated, allowing the sensors to be replaced in the event of damage. Due to the universality of the signal interrogation, the instrument can be compatible with any interferometric point sensor which has a similar optical path difference with the transmitting interferometer or any fiber grating sensor whose normal wavelength is within the spectral range of the light source. In addition, as the total sensor number which can be multiplexed is quite large, the average cost for each sensor is reduced considerably. Therefore, this system allows optical fiber sensors to compete with conventional sensors with the additional benefits of fiber-optic sensors     

Theoretical model of a fiber optic remote sensor based on surface plasmon resonance for temperature detection

This paper reports on a novel design of a remote sensor for temperature detection based on surface plasmon resonance and optical fiber technology. We theoretically analyze the performance of proposed sensor under different conditions related to its constituents, i.e., optical fiber, metallic layer, sensing region, and launched light. The effect of the related parameters such as numerical aperture, fiber length, core diameter, FWHM of the Gaussian input on sensor is analyzed along with its physical explanation. The numerical results presented in this paper leads to a significant optimization of the important design parameters to achieve a high temperature detection accuracy and sensitivity of a fiber optic remote sensor.     

Fiber Optical Intensity Sensors

Fiber optical intensity sensors are made of optical fibers connected to a miniaturized optical sensor which is based on either a mechanical light valve, a light scattering process, a photoemission or photoabsorption process, or the transmission property of the optical fiber itself. Use of the optical fiber to transmit light to and from the optical sensor makes it possible to construct an electrically passive sensor with remotely located electronic readout capability. Major advantages of this type of sensors are electromagnetic interference immunity, electrical passiveness and safety, miniature size, and ruggedness, In this paper, the large variety of fiber optical intensity sensors reported to date will be classified by their sensing mechanism. Examples will be given for each category of sensors with reported performances.     

全光纤微型珐-珀干涉式高温传感器

通过在单模光纤SMF28e后有轴心偏移地熔接一段特种光子晶体光纤(MM-HNA-5)制作了一种全光纤微型珐-珀(F-P)干涉仪.分析了这种干涉仪的光学原理和形成机理,并利用MM-HNA-5光纤热光系数较大的特点,将这种干涉仪应用于温度测量.实验结果表明:这种干涉传感器可测量的高温范围可达1 200℃,远大于常规传感器的测量范围,且当干涉腔长为3.46 mm 时,其光程差的温度灵敏度约为103 nm/℃,线性度为O.995 7.可以预见:这种结构稳定、体积小、精度高、测温范围广的全光纤F-P干涉温度传感器在国防及民用工业中将具有极大的潜在应用价值.     

MRI-compatible intensity-modulated force sensor for cardiac catheterization procedures

This paper presents a novel, magnetic resonance imaging (MRI)-compatible, force sensor suitable for cardiac catheterization procedures. The miniature, fiber-optic sensor is integrated with the tip of a catheter to allow the detection of interaction forces with the cardiac walls. The optical fiber light intensity is modulated when a force acting at the catheter tip deforms an elastic element, which, in turn, varies the distance between a reflector and the optical fiber. The tip sensor has an external diameter of 9 Fr (3?mm) and can be used during cardiac catheterization procedures. The sensor is able to measure forces in the range of 0-0.85?N, with relatively small hysteresis. A nonlinear method for calibration is used and real-time MRI in vivo experiments are carried out, to prove the feasibility of this low-cost sensor, enabling the detection of catheter-tip contact forces under dynamic conditions.     

Bragg光纤的基本理论分析与设计

光通信、光传感等领域的技术迅速发展对光纤的性能提出了新的要求,促使人们提出了许多新型折射率结构的光纤,其中Bragg 光纤就是其中的一种新型折射率光纤,他有很多普通光纤无法比拟的优势。为了更加全面的分析Bragg 光纤的基本理论,首先以普通同轴分层光纤为例介绍了转移矩阵法的基本思想。接着将这一理论应用于Bragg 光纤的模场计算,然后把有限包层布拉格光纤的模式作为无限包层情形的退化来分析,进一步研究Bragg光纤的设计原则。     

分布式光纤温度传感器信号处理系统的研究

信号处理系统是分布式光纤温度传感器的重要组成部分，它的研究和设计对降低探测器和放大器的输出噪声，提高传感器的时间分辨率和温度分辨率有重要的意义。本文从提高时间分辨率的角度介绍了传感器对信号处理系统的要求，提出并行取样积分器方案及其所能达到的时间分辨率；介绍了由此而建立的信号处理系统。     

Design and characteristic analysis of fiber optic Fabry-Perot sensor for static ice strain monitoring

Sea ice is one of the important natural disasters.A new method based on optical fiber Fabry-Perot sensor for ice strain measurement was proposed to meet the needs of ice strain monitoring.A high sensitivity optical fiber Fabry-Perot pressure sensor with thin-film structure was realized by means of pressure assisted arc discharge method,and the sensor was encapsulated by metal tube /PDMS /AB epoxy glue combination method.On this basis,the static internal strain characteristics of ice in the process of melting and freezing during -15℃～0℃ was studied.Experimental results show that this proposed thin-film fiber Fabry-Perot pressure sensor has good sensitivity characteristic in ice strain monitoring,it is believed of great value for the monitoring of remote distributed sea samples.     

分布式光纤传感技术在蜗壳模型试验中的应用

分布式光纤传感器与传统应变片和光纤光栅传感器相比,具有分布式测量的显著特点,成为传感器领域的研究热点。随着技术的进步,基于瑞利散射的光频域反射技术(OFDR)得到了迅速的发展。该文介绍了OFDR的测量原理,并将分布式光纤传感器应用于蜗壳模型试验中。为检验蜗壳充水后的变形规律,检查蜗壳和混凝土的整体安全性和设计的合理性,对蜗壳试验过程中外围混凝土应变进行监测。通过分布式光纤传感器在每级水压加载下产生的应变,获得蜗壳模型外部变形以及裂缝发展的情况。实验结果表明,分布式光纤传感器能够真实地反应结构物的应变分布,及时准确地监测蜗壳模型在加压作用下混凝土变形及开裂情况,对结构的损伤进行识别。