多模与Sagnac复合干涉型振动传感器  

Research on Fiber Sagnac Vibration Sensor Based on Multi-mode Fiber Coupler

作　　者：田野 黎键 杨光 赵敏 陈海艳 王晓航 TIAN Ye;LI Jian;YANG Guang;ZHAO Min;CHEN Haiyan;WANG Xiaohang(West Pipeline Co.,Ltd.,PipeChina;Xinjiang Key Laboratory for Transportation Safety of Multi-Medium Pipelines;Beijing Sheng Chuang New Technology Development Co.,Ltd.)

机构地区：[1]国家管网集团西部管道有限责任公司 [2]新疆多介质管道安全输送重点实验室 [3]北京声创新技术发展有限责任公司

出　　处：《油气田地面工程》2024年第10期75-80,共6页Oil-Gas Field Surface Engineering

摘　　要：传统光纤振动传感器可测量的振动频率范围有限,为进一步提高光纤振动传感器的频率识别能力,利用多模光纤(MMF)耦合器构建萨格纳克(Sagnac)干涉仪,将多模干涉与Sagnac干涉相结合,提出了基于多模干涉的可测量振动频率的新型Sagnac干涉型振动传感器结构。利用105μm和62.5μm芯径的MMF分别制作分光比为1∶1的多模光纤耦合器,并用其构建Sagnac环。为了对比分析,利用MMF分别制作了单模-多模-单模(SMS)干涉结构及马赫增德尔干涉结构的传感器。通过大量实验对几种类型的振动传感器在振动频率检测范围、振动频率检测准确度和振动信号幅值等方面进行了详细的对比研究。研究结果表明:基于105μm芯径阶跃折射率分布MMF的Sagnac干涉结构在0.3~20 kHz的频率范围内,获得了频谱主级峰和次级峰强度差大于20 dB的频率识别效果,可测频率范围宽,主次级峰强度差大,对低频振动更灵敏,且频率偏差在Hz量级,在几种对比结构中振动测试性能最好,为振动检测的研究提供了一种新方案。The traditional fiber optic vibration sensor has a limited range of measurable vibration frequencies.To further improve the frequency recognition ability of the fiber optic vibration sensor,a multi-mode fiber(MMF)coupler is used to construct a Sagnac interferometer.Combining multi-mode interference with Sagnac interference,a new Sagnac interferometric vibration sensor structure based on multi-mode interference for measurable vibration frequencies is proposed.Using MMF with core diam-eters of 105μm and 62.5μm,multi-mode fiber couplers with a splitting ratio of 1∶1 are fabricated,and Sagnac loops are constructed by using them.For comparative analysis,sensors with single modemulti-mode-single mode(SMS)interference structure and Mach Zehnder interference structure are fabricated using MMF.A detailed comparative study is conducted on several types of vibration sensors in terms of vibration frequency detection range,vibration frequency detection accuracy,and vibration signal amplitude through extensive experiments.The research results show that the Sagnac interferometric structure based on the 105μm core diameter step refractive index distribution MMF achieves frequency recognition in the frequency range of 0.3~20 kHz with a difference in intensity between the main and secondary peaks of the spectrum greater than 20 dB.It has a wide measurable frequency range,a large difference in intensity between the main and secondary peaks,and is more sensitive to low-frequency vibrations.The frequency deviation is in the Hz range,and it has the best vibration testing performance among several comparative structures,providing a new solution for vibration detection research.

关 键 词：振动传感器 频率测量 萨格纳克干涉仪 多模干涉 光纤耦合器 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置] TB523[自动化与计算机技术—控制科学与工程]