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新型光纤光栅技术及其在光通信与光纤传感方面应用的研究
Investigation on the Novel Technology of the Fiber Bragg Gratings and Applications in Optical Fiber Communications and Sensors
【作者】 周金龙;
【导师】 董小鹏;
【作者基本信息】 厦门大学 , 通信与信息系统, 2008, 博士
【摘要】 光纤光栅已经成为当前最具发展前途,最具代表性的光无源器件之一,在光通信与光传感领域都得到了广泛的应用。D形光纤光栅与基于光纤光栅的法珀结构是其中两种比较新型的技术,它们各自具有独特的性质,可以实际应用在许多场合,因此,研究它们具有重要的理论和实际意义。本文主要的研究工作体现在三个方面:一、光纤光栅波长解调技术及其应用的研究。研究了基于边沿滤波器及可调谐法珀滤波器的两种光栅波长解调技术,实验得到的波长分辨率分别为3.1pm和3pm。并且将这两种解调技术相结合,实际应用于桥梁结构健康监测。二、D形光纤光栅的弯曲敏感特性及其应用的研究。用材料力学理论详细分析了D形光纤光栅的弯曲敏感机理。实验测得其弯曲灵敏度比圆对称的常规光栅分别高78倍(压缩光栅)及86倍(拉伸光栅)之多。将其应用在线位移及加速度的测量中,实验获得的灵敏度分别为-0.27nm/mm及0.191nm·s~2/m。提出了将D形光纤光栅弯曲成‘Ω’形状,使其啁啾化,实现了光栅色散值的可调谐;并且将其中点设置在零应变点的位置,能够保持中心波长不发生漂移。实验获得的反射谱带宽由0.299nm调谐到2.057nm,同时中心波长漂移小于17pm。三、基于光纤光栅的法珀结构的原理及应用的研究。提出了光纤光栅法珀滤波器具体的设计和制作方法。并将这种滤波器应用在光纤激光器以及微波信号的光子学生成技术中。实验分别获得了波长可调谐的19个单波长激光和18对双波长激光,以及9.4885~10.0712GHz一系列频率的微波信号。提出了基于光纤光栅法珀结构的可调谐相移光栅。建立了理想模型及实际模型两种仿真模型,详细的分析讨论了各个参数对相移光栅透射谱的影响。与传统的腐蚀光栅法相比,这种新型的可调谐相移光栅在折射率传感中能够大幅提高灵敏度。
【Abstract】 Fiber Bragg gratings have become one of the most promising and representative optical passive devices at present,and have been broadly applied in optical fiber communications and sensors.The D-shaped fiber Bragg grating(D-FBG) and FBG based Fabry-Perot structure are two novel techniques,which can be applied in many areas for their special properties.So it is really important for theory and practical applications to study them.In this dissertation,the author investigates some problems in FBG techniques as follows:1.Investigation on the wavelength demodulation techniques of FBG and the applications.Two techniques of wavelength demodulation based on the linear edge filter and the tunable Fabry-Perot filter(FPF) are investigated.The experimental wavelength resolutions are 3.1pm,and 3pm,respectively.Then,both of them are cooperated and applied in the health monitoring of bridge structure.2.Study on the bending sensitivity of the D-FBG and its applications.The bending sensitivity of the D-FBG is analyzed with mechanics of material in detail.The experimental results are 78 times(compression) and 86 times(stretch) as high as the uniform FBG’s,respectively.Then the D-FBGs are applied in sensors of linear displacement and acceleration,and the sensitivity of-0.27nm/mm and 0.191nm·s~2/m are obtained,respectively,in experiment.A novel method is proposed for tuning the grating’s dispersion through bending the D-FBG into theΩ-shape in order to chirp it. The central wavelength of the D-FBG can be kept no shift by locating its center at the zero strain point.The bandwidth of the reflection spectrum is significantly tuned from 0.299nm to 2.057nm,while the central wavelength shift is within 17pm.3.Research work on the FBG based Fabry-Perot structure and its applications.The method for designing and fabricating the FBG based FPF is demonstrated concretely. Thus,such FPFs are applied in optical fiber ring laser and photonic generation of microwave.Nineteen single-wavelength lasings,eighteen pairs of dual-wavelength lasings,and a series of microwave signals with frequency from 9.4885GHz to 10.0712GHz are experimentally obtained,respectively.A novel tunable phase-shift FBG(PS-FBG) based on such Fabry-Perot structures is proposed.Two modes, including the ’ideal mode’ and the ’practical mode’,are created for simulation.The influence on the PS-FBG’s transmission spectrum induced by the parameters is discussed.Compared with the traditional FBG-etching method,the sensitivity of such PS-FBG is much higher when it is applied in refractive index sensing.
【Key words】 Fiber Bragg grating; wavelength demodulation; D-shaped fiber Bragg grating; Fabry-Perot filter; phase shift fiber Bragg grating;