A tension insensitive PbS fiber temperature sensor based on Sagnac interferometer

In this paper, a tension insensitive PbS fiber temperature sensor based on Sagnac interferometer is proposed and demonstrated. The sensing mechanism of tension and temperature is analyzed. The relationships between the interference spectrum, temperature and tension are analyzed, respectively. The experimental temperature range is 36—70 °C. The experimental results show that the interference spectrum is red shifted, and its sensitivity is 53.89 pm/°C. In tension experiment, the tension range is 0—1 400 με. The experimental results show that there is no wavelength shift in the interference spectrum. The sensor is immune to tension cross-sensitivity compared with other sensors. It can be used for temperature testing in aerospace, chemistry and pharmacy.     

光子晶体光纤光栅谐振波长的特性研究

应用多极法理论和传输矩阵法,对基于包层空气孔为正六边形对称结构的光子晶体光纤的布喇格光栅特性进行了计算和仿真。对比研究了常规单模光纤所成光栅与相同光栅周期的光子晶体光纤布喇格光栅反射谱之间的差异,重点研究了光子晶体光纤的结构参数变化（间隙孔半径、层数）与光子晶体光纤光栅的谐振峰变化规律。当光子晶体光纤的间隙孔半径增大时,光子晶体光纤光栅的谐振波长出现蓝移;当光子晶体光纤的间隙孔径不变而层数增加时,光子晶体光纤光栅的谐振波长出现红移。     

光子晶体光纤熔接损耗研究

基于有限元法分析了光子晶体光纤模场半径,为了提高计算速度,提出了一种工作波长为1．55μm时,光子晶体光纤模场半径的快速估算方法,进而实现光子晶体光纤熔接损耗的快速估算。分析表明,本文提出的方法能够准确快速的实现光子晶体光纤熔接损耗的估算。     

基于聚合物绝缘栅的低电压有机薄膜晶体管

利用甲基丙烯酸甲酯-甲基丙烯酸环氧丙脂为栅绝缘层制备了酞箐铜有机薄膜晶体管,在电压为10V时器件具有较好的性能,栅绝缘层的漏电流密度低至2×10-8A/cm2 。测量其电容特性,该绝缘薄膜的介电常数介于3.9-5.0 。通过对绝缘层的减薄,阈值电压由 -3.5V 升至-2.0V,该酞箐铜有机薄膜晶体管可以在低电压下工作,其场效应迁移率为1.2×10-3 cm2/Vs 。     

Low voltage copper phthalocyanine organic thin film transistors with a polymer layer as the gate insulator

Low voltage organic thin film transistors(OTFTs) were created using polymethyl-methacrylate-co g-lyciclyl-methacrylate(PMMA-GMA) as the gate dielectric.The OTFTs performed acceptably at supply voltages of about 10 V.From a densely packed copolymer brush,a leakage current as low as 2×10~(-8) A/cm~2 was obtained.From the measured capacitance-insulator frequency characteristics,a dielectric constant in the range 3.9-5.0 was obtained. By controlling the thickness of the gate dielectric,the threshold voltage ...     

基于虚拟仪器的智能感知专家系统的设计

集成了网络通信、嵌入式系统、虚拟仪器、人工智能专家系统等前沿技术,构成基于虚拟仪器的智能感知专家系统,由智能感知单元对运行中设备状态实时监测,经无线网络送入基于虚拟仪器的免编程专家系统,对设备实施科学的故障预报,实现预知性维修,开创从传统的预防维护上升到预知维护的先河.     

光纤Bragg光栅的反射特性研究

阐述了由耦合模理论得到的光纤Bragg光栅的反射率的表达式 ,并且由此表达式导出了光纤Bragg光栅的反射特性 ,反射中心波长为λB=2 ·neff·Λ。进而理论分析了反射波长λ、光栅栅距Λ ,折射率微扰的最大值Δnmax、光栅区长度L和反射率Rg 之间的关系。     

桥梁检测中光纤传感技术的研究综述

本文论述了光纤传感技术在国内外桥梁检测中的研究与应用；并以应变检测为例介绍光纤传感技术在检测桥梁中的检测原理、方法与最新研究成果，文章最后指出桥梁检测中光纤传感技术的发展方向。     

Refractive index insensitive temperature sensor based on waist-enlarged few mode fiber bitapers

A refractive index insensitive temperature sensor based on waist-enlarged few mode fiber (FMF) bitapers is presented. The first section of FMF is spliced between two single-mode fibers. In fusion process, the waist-enlarged FMF bitapers can be obtained by large current discharging repeatedly. The refractive index and temperature sensing mechanisms are analyzed. For the sensors with different sizes, the refractive index and temperature experiments have been performed. The results show that in the refractive index ranges of 1.335 0—1.346 6 and 1.348 2—1.419 3, the refractive index insensitivity is verified. In a temperature range of 31.9—90 °C, the sensor sensitivity can be up to 85.57 pm/°C. In addition, it has a compact structure. Therefore, the sensor can avoid the cross sensitivity for measuring the refractive index and temperature simultaneously.