基于光纤布里渊动态光栅的超高分辨光谱分析机理研究

Ultra-high optical spectroscopy has always been the primary basis for optical measurement and test. In recent years, the spectral resolution of the traditional optical spectrum analyzer has already been the “bottleneck” for some novel applications. To push the spectral resolution limited by the existing technologies, this project proposes a novel optical spectroscopy based on Brillouin dynamic gratings (BDGs) in optical fibers, where a coherent laser is used to excite a long BDG with a narrow reflection spectrum for an ultra-high resolution spectroscopy. Using a liquid-core fiber to excite a BDG, it is expected to achieve an ultra-high optical spectroscopy with a wide wavelength coverage, a high dynamic range and multiple functions. The content of the research includes the followings: the fabrication and characterization of low-loss, robust, high-nonlinear and low-birefringence liquid-core fibers, the excitation of a uniform BDG with a wide wavelength coverage, and the polarization-diversity scheme for the simultaneous measurement of spectrum and polarization. The project aims to an ultra-high optical spectroscopy with a wavelength coverage of S+C+L, sub-fm spectral resolution (superior to 0.1MHz) and the capability of simultaneous measurement of spectrum and polarization, and it will be important for the applications of the diagnostic of signals in optical communication and high-accuracy optical sensing and measurement.

超高分辨光谱分析技术一直以来都是光学检测和测量中最基本和最重要的研究方向。近年来，传统光谱仪的分辨率已经逐渐不能满足新型应用的需求，成为新兴领域发展的瓶颈。为突破现有技术对光谱分辨率的限制，本项目提出基于光纤中布里渊动态光栅的光谱分析方法，采用高相干度激光激发较长的布里渊动态光栅从而获得极窄的反射谱和超高的光谱分辨率。项目以液芯光纤为载体激发布里渊动态光栅，研究低插入损耗、结构稳固的高非线性、低双折射液芯光纤的制备和特性表征，研究宽波长范围扫描条件下均匀布里渊动态光栅的激发技术，研究偏振分集测量技术实现光谱和偏振态同时测量方法。研究成果有望实现波长范围覆盖S+C+L波段，光谱分辨率达到亚fm（优于0.1MHz），具备光谱和偏振态同时测量功能的超高分辨光谱分析技术，对高速光通信信号诊断、高精度光学传感和光学计量等应用具有重要意义。

超高分辨光谱分析技术一直以来都是光学检测和测量中最基本和最重要的研究方向。近年来，传统光谱仪的分辨率已经逐渐不能满足新型应用的需求，成为新兴领域发展的瓶颈。为突破现有技术对光谱分辨率的限制，本项目提出了基于光纤布里渊动态光栅的光谱分析方法，采用高相干度激光激发较长的布里渊动态光栅从而获得极窄的反射谱和超高的光谱分辨率。项目以光纤为载体激发布里渊动态光栅，研究了低插入损耗、结构稳固的高非线性、低双折射液芯光纤的制备和特性表征，研究了宽波长范围扫描条件下均匀布里渊动态光栅的激发技术，研究了偏振分集测量技术实现光谱和偏振态同时测量方法。研究成果实现了波长范围覆盖，光谱分辨率达到fm量级，具备光谱和偏振态同时测量功能的超高分辨光谱分析技术，对高速光通信信号诊断、高精度光学传感和光学计量等应用具有重要意义。在此基础上我们又拓展研究了以下内容：基于布里渊动态光栅分布式横向压力传感、基于布里渊动态光栅分布式静压力传感、高空间分辨率传感、动态分布式传感、超快分布式布里渊光纤传感、高温应变分布式布里渊光纤传感，成果应用于石油管道监测、电力线监测等领域。