基于游标效应的双芯光子晶体光纤温度传感器

设计了一种基于双芯光纤耦合效应和游标效应的高灵敏度温度传感器,传感器是由2个相差一定长度的双芯光子晶体光纤和单模光纤级联构成。双芯光子晶体光纤通过级联实现游标效应,同时对纤芯中间的气孔填充乙醇实现温度传感。仿真结果表明,该温度传感器在35℃～45℃范围内的平均温度灵敏度可达-20.37 nm/℃。与单纯依靠双芯光子晶体光纤能量耦合效应的传感器相比,该传感器的温度检测灵敏度提高了10倍。     

Miniature fiber-optic high temperature sensor based on a hybrid structured Fabry-Perot interferometer

A miniature Fabry-Perot (FP) interferometric fiber-optic sensor suitable for high-temperature sensing is proposed and demonstrated. The sensor head consists of two FP cavities formed by fusion splicing a short hollow-core fiber and a piece of single-mode fiber at a photonic crystal fiber in series. The reflection spectra of an implemented sensor are measured at several temperatures and analyzed in the spatial frequency domain. The experiment shows that the thermal-optic effect of the cavity material is much more appreciable than its thermal expansion. The temperature measurements up to 1000 degrees C with a step of 50 degrees C confirm that it could be applicable as a high-temperature sensor.     

Enhanced sensitivity of hemoglobin sensor using dual-core photonic crystal fiber

A Hemoglobin (Hb) biosensor based on dual-core photonic crystal fiber is proposed and analyzed. In this paper, the effective refractive index dependency on the Hb concentration within a blood sample is utilized in obtaining the transmission spectrum variation. The results are calculated using full vectorial finite element method. Through this study, the effect of the structure geometrical parameters on the sensor performance is optimized to maximize the sensor sensitivity. The numerical results show a sensitivity of 8.013 nm/g/dL for the X-polarized mode at 3.7 cm fiber length and 7.68 nm/g/dL for the Y-polarized mode at 3.2 cm fiber length of the proposed sensor.     

Curvature sensor based on a pressure-induced birefringence single mode fiber loop mirror

An optical fiber curvature sensor based on a pressure-induced birefringence singlemode fiber loop mirror is presented. The birefringer SMF is made by applying a transverse force against a short length of singlemode fiber. The length of the sensing element for the curvature sensing is about 150 mm. The sensitivity of the curvature measurement experimentally is 0.0263 m⁻¹/pm. And the temperature effect of the proposed sensor is also analyzed. Comparing with the sensor of photonic crystal fiber, it is more convenient and simply.     

High sensitivity plasmonic temperature sensor based on a side-polished photonic crystal fiber

A high sensitivity plasmonic temperature sensor based on a side-polished photonic crystal fiber is proposed in this work.In order to achieve high sensitivity and high stability,the gold layer is coated on the side-polished photonic crystal fiber to support surface plasmon resonance.The mixture of ethanol and chloroform is used as the thermosensitive liquid.The performances of the proposed temperature sensor were investigated by the finite element method(FEM).Simulation results indicate that the sensitivity of the temperature sensor is as high as 7.82 nm/℃.It has good linearity(R;=0.99803),the resolution of 1.1×10;℃,and the amplitude sensitivity of 0.1008℃;.In addition,the sizes of the small air hole and polishing depth have little influence on the sensitivity.Therefore,the proposed sensor shows a high structure tolerance.The excellent performance and high structure tolerance of the sensor make it an appropriate choice for temperature measurement.     

基于侧漏型光子晶体光纤高灵敏度宽线性范围弯曲传感器的研究

基于所研制的侧漏型光子晶体光纤, 提出并研制出一种Sagnac干涉仪型高灵敏度宽线性测量范围的弯曲传感器. 实验研究结果表明, 当侧漏型光子晶体光纤中的线性缺陷与弯曲方向一致时, 采用群双折射和波谷波长偏移量测量弯曲曲率均可获得高的弯曲灵敏度, 但线性测量范围小, 且不能进行小弯曲曲率的测量. 当线性缺陷与弯曲方向垂直时, 以波谷波长偏移量进行弯曲曲率检测, 可获得10.798 nm/m^-1高灵敏度的同时且可实现0–5.03 m^-1的宽线性测量范围, 结合测量矩阵的引入可实现温度和弯曲曲率的同时测量, 进而剔除环境温度变化对弯曲曲率检测的干扰, 实现了高灵敏度宽线性范围的弯曲传感; 而以群双折射进行弯曲曲率检测, 虽然检测灵敏度较低, 但可实现对环境温度不敏感的弯曲传感. 关键词： 弯曲传感器 侧漏型光子晶体光纤 高灵敏度 宽线性范围     

基于椭球封闭空气腔的光纤复合法布里-珀罗结构折射率传感特性研究

提出了基于微椭球型空气腔的在线型光纤复合法布里-珀罗干涉结构,并对其折射率传感特性进行了研究.椭球型空气微腔是利用光纤熔接机对实芯光子晶体光纤和单模光纤以特定的熔接参数熔接形成.用高斯光束模型和ABCD法则分析了椭球型空气腔的腔内损耗,建立了电磁场在复合法布里-珀罗干涉结构中传播的物理模型.根据腔长比值的不同,环境折射率对干涉条纹的影响有对比度调制和波长调制,主要研究了一种波长调制型复合法布里-珀罗结构折射率传感器.仿真结果表明该折射率传感器在1—1.6范围内不出现折射率转折点;实验结果表明在1.333—1.466范围内,折射率灵敏度～37.088 nm·RIU-1,分辨率约为2.69×10-5.该光纤复合法布里-珀罗结构干涉条纹对比度高、体积小、成本低,用于折射率测量可靠性高、分辨率高、无折射率拐点、温度串扰小.     

Fabry–Pérot cavities based on chemical etching for high temperature and strain measurement

In this paper, two hybrid multimode/single mode fiber Fabry–Pérot (FP) cavities were compared. The cavities fabricated by chemical etching are presented as high temperature and strain sensors. In order to produce this FP cavity a single mode fiber was spliced to a graded index multimode fiber with 62.5 μm core diameter. The Fabry–Pérot cavities were tested as a high temperature sensor in the range between room temperature and 700 °C and as strain sensors. A reversible shift of the interferometric peaks with temperature allowed to estimate a sensitivity of 0.75 ± 0.03 pm/°C and 0.98 ± 0.04 pm/°C for the sensor A and B respectively. For strain measurement sensor A demonstrated a sensitivity of 1.85 ± 0.07 pm/μ? and sensor B showed a sensitivity of 3.14 ± 0.05 pm/μ?. The sensors demonstrated the feasibility of low cost fiber optic sensors for high temperature and strain.     

High-pressure and high-temperature characteristics of a Fabry-Perot interferometer based on photonic crystal fiber

A fiber-optic Fabry-Perot interferometer was constructed by splicing a short length of photonic crystal fiber to a standard single-mode fiber. The photonic crystal fiber functions as a Fabry-Perot cavity and serves as a direct sensing probe without any additional components. Its pressure and temperature responses in the range of 0-40 MPa and 25°C-700°C were experimentally studied. The proposed sensor is easy to fabricate, potentially low-cost, and compact in size, which makes it very attractive for high-pressure and high-temperature sensing applications.     

Simultaneous measurement of temperature and strain using a long-period fiber grating with a micro-taper

An all-fiber Mach–Zehnder interferometer (MZI) consisting of a long-period fiber grating with a micro-taper is proposed for simultaneous measurement of temperature and strain. The experimental results demonstrate that the temperature and strain sensitivities of the proposed MZI are 83 pm/°C and ?2.6 pm/με, respectively. The strain sensitivity is 20 times as high as that of a long-period fiber written by CO₂ laser pulses combined with a fiber bitaper. In addition, the interferometer requires only a common single-mode fiber, and it is easy to fabricate and is inexpensive for temperature and strain sensing applications.     

基于空芯光子晶体光纤的微小型非本征光纤法布里-珀罗干涉应变传感器

报道了一种用空芯光子晶体光纤制作的法布里-珀罗腔体,利用光纤熔接方法将该法布里-珀罗腔体和两根普通通信单模光纤熔接起来构成的微小型光纤法布里-珀罗干涉应变传感器。这种干涉传感器制作过程仅应用了切割和熔接手段,光纤材料单一,因此受温度变化的影响小。另外,该类型传感器的干涉腔长度对干涉信号强度影响不大,其干涉腔长度可至数厘米。因此,这类传感器将在大容量、准分布式传感系统中具有极大的潜在应用价值。     

Axial strain and temperature sensing characteristics of the single–coreless–single mode fiber structure-based fiber ring laser

This paper experimentally demonstrated a singlemode–coreless–singlemode (SCS) fiber structure-based fiber ring cavity laser for strain and temperature measurement. The basis of the sensing system is the multimodal interference occurs in coreless fiber, and the transmission spectrum is sensitive to the ambient perturbation. In this sensing system, the SCS fiber structure not only acts as the sensing head of the sensor but also the band-pass filter of the ring laser. Blue shift with strain sensitivity of \(\sim\) ?2 pm/με ranging from 0 to 730 με and red shift with temperature sensitivity of \(\sim\) 11 pm/°C ranging from 5 to 75 °C have been achieved. Experimental results also show the proposal has great potential in using long-distance operation. The fiber ring laser sensing system has a optical signal to noise ratio (OSNR) more than 50 and 3 dB bandwidth less than 0.05 nm. The result shows that the coreless fiber has no improvement of the temperature and axial strain sensitivity. However, compared to the common singlemode–multimode–singlemode fiber structure sensors, the laser sensing system has the additional advantages of high OSNR, high intensity and narrow 3 dB bandwidth, and thus improves the accuracy.     

同时测量扭转角度和扭转方向的侧漏光子晶体光纤扭转传感器

基于所研制的侧漏型光子晶体光纤,提出并构建了出一种同时检测扭转角度 和扭转方向的高灵敏度Sagnac干涉仪型光纤扭转传感器.顺时针扭转时, 传感器传输谱向短波长方向偏移;逆时针扭转,向长波长方向偏移. 对传感器扭转特性的实验研究结果表明,构成Sagnac干涉仪的侧漏型光子晶体光纤的长度, 对扭转敏感系数和扭转角度测量范围起着决定性作用.当光纤长度较短时, 扭转传感器具有较大的扭转灵敏度,但扭转角度测量范围较小;光纤长度增加时,扭转灵敏度减小, 扭转角度测量范围增大.当构成Sagnac干涉仪的侧漏型光子晶体光纤长度为14.85 cm时, 传感器的扭转敏感系数可达到0.9354 nm/(°),扭转角度测量范围为-90°—90°; 光纤长度为32 cm时,最大扭转敏感系数降为0.2132 nm/(°), 扭转角度测量范围扩展至-180°—180°. 采用二维测量矩阵法可以有效排除温度对扭转角度的测量的影响. 关键词： 光纤传感器 侧漏型光子晶体光纤 扭转传感器 Sagnac干涉仪     

Fabry-Perot optical fiber tip sensor for high temperature measurement

We propose a novel Fabry-Perot optical fiber tip sensor for high temperature measurement. The sensor consists of a short section of a special all-silica photonic crystal fiber spliced at one end to a silica single-mode fiber. Because of its all-silica structure, the sensor allows linear and stable measurements of temperature up to 1200 °C with a high sensitivity. The sensor is easy and inexpensive to fabricate and could find wide applications in mechanics, aeronautics, and metallurgy.     

超低温度系数的光子晶体光纤Sagnac压力传感器

 提出了一种基于光子晶体光纤Sagnac干涉仪的横向压力传感器。使用的光子晶体光纤为低双折射光纤,首先预先在Saganc环中的光子晶体光纤上施加初始压力,使Sagnac干涉仪产生正弦干涉光谱,然后再将被测物体放在光子晶体光纤上,由于被测物体重力的作用,Saganc干涉仪输出的光谱产生移动,实现横向压力传感测量。传感器具有高灵敏度0.529 nm/(N·mm)及超低的温度系数-0.4 pm/℃,其环境温度的影响可以忽略。     

Intensity measurement based temperature-independent strain sensor using a highly birefringent photonic crystal fiber loop mirror

A fiber-optic strain sensor is demonstrated by using a short length of highly birefringent photonic crystal fiber (HiBi-PCF) as the sensing element inserted in a fiber loop mirror (FLM). Due to the ultralow thermal sensitivity of the HiBi-PCF, the proposed strain sensor is inherently insensitive to temperature. When a distributed-feedback (DFB) laser passes through the FLM, the output power is only affected by the transmission spectral change of the FLM caused by the strain applied on the HiBi-PCF. Based on intensity measurement, an optical power meter is adequate to deduce the strain information and an expensive optical spectrum analyzer (OSA) would not be needed.     

高温光子晶体光纤温度传感器

针对大于500℃的高温环境,提出了一种可用于高温温度测量的高温光子晶体光纤(PCF)温度传感器。在光子晶体光纤末端熔接一段纯石英无芯光纤构成外腔式光纤法珀腔(EFPI)结构。纯石英无芯光纤在高温下的热膨胀和热光效应使得EFPI的光学腔长发生变化。结合光纤白光干涉测量技术,通过测量EFPI的腔长得到被测温度。在不同温度环境下,对腔长为175μm的EFPI光纤温度传感器进行连续测量。测量结果显示,设计的高温光纤温度传感器在27~1100℃范围内,腔长-温度三阶拟合精度达到99.95%,腔长-温度灵敏度为(0.851+0.0023T-0.000000957T2)nm/℃,其中在1100℃时,温度测量分辨率为0.225℃。     

应用于液压传感的光子晶体光纤特性

为实现结构紧凑、高灵敏度的光纤压力(液压)传感器,提出了一种应用于液压传感的边孔结构光子晶体光纤.基于全矢量有限元方法,研究了传统光子晶体光纤和边孔结构光子晶体光纤的有效折射、模式等特性以及在液压情况下的应力和应力特性.根据光弹效应给出了传统光子晶体光纤和边孔结构光子晶体光纤在液压情况下的折射率变化特性.模拟结果表明边孔结构光子晶体光纤可以获得更大的液压传感灵敏度,增大边孔半径可以提高液压传感灵敏度,因此结构优化的边孔结构光子晶体光纤可以实现高灵敏度的光纤压力(液压)压力传感器.     

应用于液压传感的光子晶体光纤特性

为实现结构紧凑、高灵敏度的光纤压力(液压)传感器,提出了一种应用于液压传感的边孔结构光子晶体光纤.基于全矢量有限元方法,研究了传统光子晶体光纤和边孔结构光子晶体光纤的有效折射、模式等特性以及在液压情况下的应力和应力特性.根据光弹效应给出了传统光子晶体光纤和边孔结构光子晶体光纤在液压情况下的折射率变化特性.模拟结果表明边孔结构光子晶体光纤可以获得更大的液压传感灵敏度,增大边孔半径可以提高液压传感灵敏度,因此结构优化的边孔结构光子晶体光纤可以实现高灵敏度的光纤压力(液压)压力传感器.     

All-solid multi-core fiber-based multipath Mach–Zehnder interferometer for temperature sensing

A novel multipath Mach–Zehnder interferometer (m-MZI) is proposed and experimentally demonstrated, which is fabricated by fusion splicing a segment of all-solid multi-core fiber (MCF) between two sections of single mode fiber-28 with a well-controlled lateral offset at the splice points. Beam propagation method-based simulation results demonstrated light passing throw MCF from multiple paths. Experiments with different lengths of MCF were implemented to investigate our proposed m-MZI’s response to temperature and strain. Compared with previously reported optical fiber modal interferometers, higher phase sensitivity can be obtained in our scheme due to the multipath interference configuration embedded in one fiber. A very high temperature sensitivity of 130.6 pm/°C has been achieved, and the maximum strain sensitivity is less than 0.284 pm/με in all experiments. A record low strain-to-temperature cross-sensitivity of 6.2 × 10^?4 °C/με has been realized, and it shows great significance of this in-fiber integrated multipath Mach–Zehnder interferometer in practical temperature sensing applications.