高双折射光纤环形镜传感信号解调方法及应用研究

发布时间：2017-12-31 12:31

本文关键词：高双折射光纤环形镜传感信号解调方法及应用研究　出处：《安徽大学》2016年博士论文　论文类型：学位论文

【摘要】：基于高双折射光纤环形镜结构的传感器具有自身组成简单、传输回路稳定、对光源偏振不敏感等优势,其传感信号解调精度高,是光纤传感领域中极具发展潜力的一类传感器。论文重点研究了高双折射光纤环形镜传感信号解调方法及其应用,基于输出光谱中相邻极小值波长,提出干涉级数测量方法。该方法和传统传感解调方法相比,解决了量程小、只能进行相对值测量等问题,实现了高精度、大量程、绝对值测量。论文探讨了该方法的适用范围,并将其成功应用在光纤拍长测量、温度传感和折射率传感等方面,具体内容如下：(1)针对现有高双折射光纤环形镜传感信号解调方法量程小、只能进行相对值测量等不足,我们提出一种基于干涉光谱相邻极小值波长测量的信号解调方法,简称“干涉级数测量法”。该方法依据相邻极小值波长计算出极值所在的干涉级数,利用该干涉级数为整数的基本属性可消除因光谱读数而引入的误差。根据干涉级数实现对高双折射光纤正交偏振模干涉相位差绝对值的测量,利用该相位差和外界参量的变化关系实现对传感信号的解调。论文分析了此方法的误差特征,并提出该方法有效工作的判据方程。(2)利用干涉级数测量法,开展了对高双折射光纤拍长测量的研究。该方法的拍长测量精度只与待测光纤长度测量精度有关,与光谱测量精度无关,克服了传统宽带光源测量方法中光谱读数误差的影响,具有测量精度更高、稳定性更好,方法更简单等优势。论文依据上述方法对熊猫型光纤拍长测量进行了数值模拟和实验研究,结果表明,拍长的测量不确定度优于0.001mm,与理论分析一致。和现有达到类似测量精度的方法相比,论文所建立的拍长测量方法更简单、对测量设备的要求更低。(3)利用干涉级数测量法,对应力型高双折射光纤环形镜的温度传感进行了研究,对比了光谱移动法、干涉级数测量法等信号解调方法各自的特点,干涉级数测量法可实现大量程、绝对值测量,其测量精度与光谱移动法相同。实验实现了30℃-350℃变化范围的测量,实际测得了干涉光谱中干涉级数,确定了干涉相位差与温度变化之间的关系,温度测量灵敏度为0.20 rad/℃,分辨率为0.04℃,不确定度为0.09℃。实验结果与理论分析一致,传感量程在已知文献类似传感器中是最大的。(4)利用干涉级数测量法,对应力型高双折射光纤环形镜在折射率方面的测量进行了研究。实验中采用化学刻蚀工艺对熊猫型光纤进行了径向刻蚀,利用干涉级数测量法实现了光纤刻蚀过程在线精确控制,得到了一种对外界折射率有强依赖性的应力区缺失结构光纤,获得了456nm/RIU的传感灵敏度,分辨率为4.4X10-5。此在线精密控制方法解决了传统工艺中依靠刻蚀时间、氢氟酸浓度控制而导致刻蚀重复性不好的问题。论文对基于高双折射光纤环形镜结构的传感器信号解调方法进行了系统研究,提出了干涉级数测量法,并将之用于拍长测量、温度传感、折射率传感等,为此类传感器的广泛应用提供了一种新颖的解调方法。
[Abstract]:The sensor of high birefringence fiber loop mirror structure has its simple structure based on transmission loop stability and polarization of the light is not sensitive to the advantages of the demodulation precision is high, is a kind of sensor has great potential for development in the field of optical fiber sensing. This paper focuses on the high birefringence fiber loop mirror sensing signal demodulation method and its application. The wavelength spectrum based on the minimum output, this series interference measuring method. Compared to the traditional method and sensor demodulation method, solves the small range, only the relative value measurement and other issues, to achieve high precision, large range, absolute value measurement. This paper discusses the scope of the method, and successfully applied in fiber beat length measurement, temperature sensor and refractive index sensing etc., the specific contents are as follows: (1) according to the range of existing high birefringence fiber loop mirror sensing signal demodulation method is small, only Can the relative value measurement problems, we propose a signal demodulation method for wavelength measurement of interference spectrum based on the minimum value of the adjacent, referred to as "series interference measurement method. The method based on the minimum wavelength to calculate the adjacent interference series extreme where the use of the basic properties of integer series interference can eliminate the error caused by the spectrum reading. According to the interference measurement series phase difference of the absolute value of high birefringence fiber orthogonal polarization mode, the relationship between the phase difference and the external parameters to demodulate the sensing signal. This paper analyzes the error characteristics of this method, the criterion equation and put forward the effective work of the method. (2) the use of interference series of measurements, carried out the research on the high birefringence fiber beat length measurement. The beat length measurement accuracy of this method is only related to fiber length measurement precision to be measured, and the spectral measurement precision Regardless of their degree, overcome the influence of spectral reading error of the traditional broadband light source measurement method, has higher precision, better stability, simpler methods and other advantages. Based on the method of PANDA fiber beat length measurement are studied by numerical simulation and experiment, the results show that the uncertainty is better than 0.001mm beat length measurement. Consistent with the theoretical analysis. Compared with the existing similar methods to the measurement precision of beat length measurement method in the paper is more simple, the measurement equipment requirements lower. (3) using series interference measuring method, temperature sensing stress type high birefringence fiber loop mirror is studied, comparing the spectral shift method. The characteristics of interference series measurement signal demodulation method of the interference measurement series method can realize large range, absolute value measurement, the measurement accuracy and spectral analysis. The same experiment achieved a 30 DEG -350 DEG variable The measurement range of the actual measured spectral interference in the series, the relationship between interference phase difference and the change of temperature to determine the temperature measurement sensitivity is 0.20 rad/ C, resolution 0.04 C, uncertainty is 0.09 degrees centigrade. The experimental results agree with the theoretical analysis, the sensing range is the largest in the known literature similar sensors. (4) using series interference measurement method, the stress of high birefringence fiber loop mirror in refractive index measurement were studied. Experiment by chemical etching process of PANDA fiber of radial etching, the interference level measuring method to realize accurate control of optical line etching process and get a the strong dependence of the stress area lack of structure of optical fiber to external refractive index, the sensitivity of 456nm/RIU, resolution of precision control method of the online 4.4X10-5. to solve the traditional process by etching Time, HF concentration control causes the etching reproducibility problems. This paper made a systematic research on sensor signal demodulation method of high birefringence fiber loop mirror based on the structure of the proposed interference series measurement method, and used to beat length measurement, temperature sensing, refractive index sensing, provides a novel the demodulation method for wide application of such sensors.

【学位授予单位】：安徽大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN911.3;TN253

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