光子晶体光纤特性及其传感应用研究

发布时间：2018-03-08 02:04

本文选题：光子晶体光纤　切入点：传感特性　出处：《大连理工大学》2015年博士论文　论文类型：学位论文

【摘要】：光子晶体光纤(Photonic crystal fiber, PCF)具有特殊的气孔结构和导光机制,因此在光纤传感和通信领域具有巨大应用前景。本文针对PCF特性及其传感应用,对PCF中的模式及其特性、PCF长周期光栅(Long-period grating, PCF-LPG)和PCF马赫-曾德尔干涉仪(Mach-Zehnder interferometer, MZI, PCF-MZI)的特性及传感应用做了全面研究,主要内容包括以下几个方面：1.基于矢量有效折射率法研究了改变结构参数调节PCF色散的方法,发现零色散波长随占空比和比例系数变化分别有极大值和极小值的双极值特性。色散调节方法和极值特性可用于指导设计有特定色散的PCF。在800 nm附近飞秒激光器工作波长处,设计了分别具有约60 nm带宽的反常平坦色散、正常平坦色散和近零平坦色散的3种PCF。2.通过数值模拟研究了根据结构参数选择合适光栅周期指导制备PCF-LPG的方法,及优选结构参数等增强内折射率(nin)敏感特性的方法。对反共振反射型光波导PCF-LPG内折射率特性进行了研究,结果表明在高介质折射率传感领域灵敏度达到10-7 RIU/pm量级。提出并分析了PCF-LPG折射率双通道测量法：被测介质在光栅外和气孔内共同作用包层模,从而增强折射率敏感特性,制成高度灵敏的PCF-LPG折射率传感器。3.以HE11cl模为例研究PCF中包层模及其色散特性、nin特性与包层半径关系。发现半径、波长及nin变化时,环状模、HE11cl模和HE12cl模间会衍变；半径减小时,多个类似模式按相似规律变化。不同半径下同一模式的色散特性和nin特性不同；模次升高时,色散特性和nin特性整体变化和增强。发现适当减小半径可增强PCF-LPG内折射率特性。4.理论与实验研究了多种因素对PCF-MZI应变特性的影响；制作了光纤环镜反射型PCF-MZI,测试表明具有较大条纹可见度和较窄带宽,能提高分辨率,应变灵敏度为-2.53 pm/με。设计制作了具有流线型熔接区的大线径PCF-MZI,测试表明应变灵敏度为-1.77 pm/με,折射率特性很弱,此种MZI适用于折射率特性不敏感的应变传感领域。5.设计并制备了阶梯式横向大偏置结构光纤MZI折射率传感器,研究了干涉原理、谱特性和折射率敏感特性。实验结果表明此种MZI灵敏度较高,长327μm和436μm的PCF-MZI和普通单模光纤MZI的灵敏度分别为2.17*10-7 RIU/pm和3.12*10-8 RIU/pm,灵敏度随着MZI长度减小而提高。制备了横向大偏置结构PCF-MZI,理论分析了干涉原理和折射率传感机制,折射率特性测试表明长330 μmPCF-MZI的灵敏度达到6.62* 10-8 RIU/pm。两种光纤MZI适于制成高度灵敏、快速测量的折射率传感器。
[Abstract]:Photonic crystal fiber (PCF) has special stomatal structure and light conduction mechanism, so it has great application prospect in the field of optical fiber sensing and communication. In this paper, we focus on the characteristics of PCF and its sensing applications. In this paper, the characteristics and sensing applications of PCF long period grating long period gratings (PCF-LPGs) and PCF Mach Zehnder interferometers (MZI, PCF-MZI) are studied. The main contents are as follows: 1. Based on the vector effective refractive index method, the method of adjusting the dispersion of PCF by changing the structure parameters is studied. It is found that the zero-dispersion wavelength has the characteristics of maximum and minimum with duty cycle and proportional coefficient, respectively. The dispersion adjustment method and the extreme characteristic can be used to guide the design of PCF with specific dispersion. The wavelength of femtosecond laser is at 800 nm. Three kinds of PCF.2s of anomalous flat dispersion, normal flat dispersion and near-zero flat dispersion with about 60 nm bandwidth are designed. The method of choosing appropriate grating period to guide the preparation of PCF-LPG is studied by numerical simulation. The internal refractive index characteristics of antiresonance reflective optical waveguide (PCF-LPG) are studied by means of selecting structural parameters and enhancing the sensitivity of internal refractive index ninning. The results show that the sensitivity in the field of high dielectric refractive index sensing is 10 ~ (-7) RIU/pm. A two-channel PCF-LPG refractive index measurement method is proposed and analyzed. The measured medium acts on the cladding mode outside the grating and in the pores, thus enhancing the refractive index sensitivity. A highly sensitive PCF-LPG refractive index sensor .3.Take the HE11cl mode as an example to study the relationship between the cladding mode and its dispersion characteristics and the cladding radius in PCF. It is found that when the radius, wavelength and nin change, the ring mode HE11cl and HE12cl mode will evolve; The dispersion characteristics and nin characteristics of the same mode are different under different radii. It is found that the internal refractive index characteristics of PCF-LPG can be enhanced by decreasing the radius. 4. The influence of many factors on the strain characteristics of PCF-LPG is studied theoretically and experimentally. The reflective PCF-MZI of optical fiber loop mirror has been fabricated. The test results show that the PCF-MZI has large stripe visibility and narrower bandwidth, which can improve the resolution of PCF-MZI. The strain sensitivity is -2.53 pm/ 渭蔚. A large diameter PCF-MZI with streamlined weld region is designed and fabricated. The results show that the strain sensitivity is -1.77 pm/ 渭蔚, and the refractive index is very weak. This kind of MZI is suitable for strain sensing field with insensitive refractive index characteristics. A step transverse large offset fiber MZI refractive index sensor is designed and fabricated, and the interference principle is studied. Spectral characteristics and refractive index sensitivity characteristics. The experimental results show that this MZI has a high sensitivity. The sensitivities of 327 渭 m and 436 渭 m PCF-MZI and MZI are 2.17 RIU/pm and 3.12 ~ (-8) RIU-pm, respectively. The sensitivity increases with the decrease of MZI length. The transverse large bias PCF-MZI is fabricated, and the interference principle and refractive index sensing mechanism are analyzed theoretically. The measurement of refractive index characteristics shows that the sensitivity of 330 渭 mPCF-MZI is 6.62 * 10-8 RIU-pm.The two kinds of optical fiber MZI are suitable for making highly sensitive and fast measuring refractive index sensors.
【学位授予单位】：大连理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TN253

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