简易带隙型光子晶体光纤的传感应用研究

发布时间：2018-01-11 00:15

  本文关键词：简易带隙型光子晶体光纤的传感应用研究　出处：《中国计量学院》2015年硕士论文　论文类型：学位论文

  更多相关文章： 简易带隙型光子晶体光纤 模式干涉 挥发性有机物 双锥级联

【摘要】：简易带隙型光子晶体光纤是一种新型光子晶体光纤,与普通的光子晶体光纤相比,它具有较高的占空比与更宽的通频带宽,此外,由于其特殊的结构使得纤芯基模与包层模之间的耦合会被有效抑制。本论文研究了两种基于此光纤的模式干涉结构,并利用其较大占空比的结构特点进行挥发性有机物传感检测;同时为了实现基于简易带隙型光子晶体光纤锥形模式干涉结构,本文提出了一种基于CO2激光器的新型光纤拉锥技术。具体研究内容如下:1、提出并实现了两种基于简易带隙型光子晶体光纤的模式干涉结构,一种将其与单模光纤进行坍塌熔接,另一种则将挥发性有机物分子扩散进光纤空气孔内;与前者相比,基于挥发性有机物分子扩散的模式干涉光传输损耗小,且无需繁杂的塌陷熔接步骤。此外,还利用有限元法建立简易带隙型光子晶体光纤的理论模型,对其在不同环境下的模场进行分析,所得的理论分析与实验数据相符。2、提出并实现了一种基于简易带隙型光子晶体光纤内瑞利散射原理进行挥发性有机物的传感测量。将简易带隙型光子晶体光纤与单模光纤机械对准而不熔接,使得挥发性有机物分子经扩散作用进入光纤空气孔内,由于瑞利散射发生较大传输损耗,导致输出光强降低。挥发性有机物浓度越高,进入空气孔的挥发性有机物分子越多,由瑞利散射引起的传输损耗也越大。通过监测输出光的强度可实现对挥发性有机物浓度的传感测量。经实验验证,当简易带隙型光子晶体光纤长度为51 mm时,对乙醇的传感测量灵敏度为0.22 d B/ppm。3、提出了一种基于CO2激光器的新型光纤拉锥系统,并成功制作出基于单模光纤的双锥级联干涉仪,并进行相关物理量的传感测量。经实验验证,仅当两个级联锥区的直径不同时干涉峰最明显;当曲率变化为6.48-7.98 m-1时;其灵敏度可达到-25.946 nm/m-1;角度变化为0.02o-0.0375o时传感器的灵敏度为601.8 nm/o;温度变化为20-110℃对应的灵敏度为0.09 nm/℃,折射率变化为1.3394-1.422对应的灵敏度为36.3 nm/RIU。可见该干涉仪可对微小的弯曲、角度变化进行传感测量,且不易受到外界环境、温度的影响。进一步地,我们使用该系统制作出基于简易带隙型光子晶体光纤的双锥级联干涉仪,并对其传感特性进行了初步研究。
[Abstract]:Simple bandgap photonic crystal fiber is a new type of photonic crystal fiber. Compared with ordinary photonic crystal fiber, it has higher duty cycle and wider bandwidth. Because of its special structure, the coupling between core mode and cladding mode can be effectively suppressed. In this paper, two kinds of mode interference structures based on this fiber are studied. The volatile organic compounds (VOCs) were detected by using the structure characteristics of large duty cycle. In order to realize the conical mode interference structure based on simple bandgap photonic crystal fiber, a new fiber tapered technique based on CO2 laser is proposed in this paper. The specific research contents are as follows: 1. Two kinds of mode interference structures based on simple bandgap photonic crystal fiber are proposed and realized, one is to collapse and weld it to a single mode fiber, the other is to diffuse volatile organic compounds into the air hole of the fiber. Compared with the former, the interference light transmission loss based on VOC molecular diffusion is less, and there is no complicated collapse fusion step. A simple theoretical model of bandgap photonic crystal fiber is established by finite element method, and the mode field in different environments is analyzed. The theoretical analysis is in agreement with the experimental data. 2. Based on the principle of Rayleigh scattering in a simple bandgap photonic crystal fiber, the sensing measurement of volatile organic compounds is proposed and realized. The simple bandgap photonic crystal fiber is mechanically aligned with the single-mode fiber without welding. Because of the large transmission loss of Rayleigh scattering, the output light intensity decreases, and the higher the concentration of volatile organic compounds, the higher the concentration of volatile organic compounds. The more VOC molecules enter the air pore, the greater the transport loss caused by Rayleigh scattering. The sensor measurement of VOC concentration can be realized by monitoring the intensity of output light. When the length of the simple bandgap photonic crystal fiber is 51 mm, the sensing sensitivity for ethanol is 0.22 dB / ppm.3. A new fiber taper pulling system based on CO2 laser is proposed, and the double cone cascade interferometer based on single mode fiber is successfully fabricated, and the sensing measurement of related physical quantities is carried out. Only when the diameter of the two cascaded cones is different, the interference peak is most obvious. When the curvature change is 6.48-7.98 m ~ (-1); Its sensitivity can reach -25.946 nm / m ~ (-1); The sensitivity of the sensor is 601.8 nm / o when the angle is 0.02o-0.0375o; The sensitivity corresponding to the temperature variation of 20-110 鈩，

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