基于时延编码的长基线激光干涉测量方法与关键技术研究

In recent years, geological activities around the world have entered an active period, there are a number of seismic zones on China's territory, so earthquake disaster prevention and mitigation become our major livelihood needs. With high measuring resolution and wide bandwidth, laser interferometry displacement measuring method uses laser wavelength as a measuring scale. This method is applied to geophysical studies, which can effectively monitor changes in geological structure and seismic activity, and effectively promote geological hazards warning. The research carries out high-precision laser displacement measurement method and key technology, develops a measuring method based on time-delay coding for multidimensional long baseline laser interferometer, which enhances sensitivity and achieves multiplexing measurement. By means of signal post-processing techniques in the time-delay coding, the noise of the light source frequency drift is suppressed under the condition of unequal interferometric arm. By mastering the key technologies of measuring sensitivity enhancement, laser frequency noise suppression and optical system online monitoring in long baseline laser interferometer, the research on laser interferometric measurement method will achieve the improvement of measuring resolution, the expansion of the dynamic range and the extension of measurement dimensions, which could provide theoretical basis and key technical support for high-precision laser interferometric measurement method.

近年来全球地质活动进入活跃期，中国国土上存在多个地震多发带，防震减灾成为我国目前的重大民生需求。激光干涉位移测量方法是一种以光波长作为度量基准的位移测量手段，具有极高测量分辨率和较宽的测量频带。激光干涉位移测量方法应用于地球物理研究，可有效监测地质结构变化及地震活动规律，有力推动地质灾害预警研究。本课题开展高精度激光位移测量新方法与关键技术的研究，发展一种基于时延编码的多维长基线激光干涉测量方法，实现灵敏度倍增及光路的多路复用；同时借助于时延编码的信号后处理技术，实现非平衡干涉臂条件下光源频率噪声的抑制消除。通过对长基线激光干涉测量灵敏度倍增、光源噪声抑制和光路在线监测等关键方法的研究，实现长基线激光干涉测量的分辨率提高、动态范围及测量维度的扩展，为高精度光学地震测量方法奠定理论基础、提供关键技术支撑。

近年来全球进入地震活跃期，发生在我国境内的玉树地震以及稍早的汶川地震均造成严重人员伤亡，频发的地震严重影响国土安全，本研究通过构建长基线激光应变仪，测量地壳微弱振动及应变，开展二维长基线激光干涉仪研究。采用光路结构优化设计，实现光源频率噪声的抑制，通过优化干涉信号解调方法，实现系统的良好环境适应性。开展了高精度激光位移测量新方法与关键技术的研究，实现灵敏度倍增及光路的多路复用；同时借助于时延编码的信号后处理技术，实现非平衡干涉臂条件下光源频率噪声的抑制消除。通过对长基线激光干涉测量灵敏度倍增、光源噪声抑制和光路在线监测等关键方法的研究，实现了长基线激光干涉测量的分辨率提高、动态范围及测量维度的扩展。.在实验室条件下，通过标定得到激光干涉仪的分辨率达到1pm。在外场实验中，受制于实验场地的环境噪声限制，总长度为47m的长臂激光干涉仪，振动幅值测量分辨率达到10pm，等效应变阶2.13×10-13，获得了潮汐引起的岩石形变数据。