基于单腔双向飞秒光梳输出的平衡互相关大量程实时绝对测距方法的研究

Large-range and high-precision absolute distance measurement is a key technology for large-equipment precision manufacturing, space ranging and positioning, and it is one of the basis of advanced manufacturing as well.A new method of large-range and real-time absolute distance measurement based on balanced cross-correlation with single-cavity bidirectional optical frequency combs is proposed in this project, where dual-comb-based absolute distance measurement is innovatively carried out on the basis of the generation of bidirectional optical frequency combs in a single fiber ring cavity. The optical balanced cross-correlation technique of femtosecond pulses is introduced into the signal acquisition for dual-comb interferometry, coupled with time-of-flight ranging and DSP-based parallel signal processing, the measurement range, precision, reliability and real-time ability of dual-comb-based ranging system are steadily improved while the cost reduction of the measurement system is highlighted.With the study of major scientific topics, such as the excitation principle of single-cavity bidirectional optical frequency combs and frequency stabilizing mechanism, pulse coherence and parameter optimization of single-cavity-based dual combs, modeling analysis of absolute distance measurement by balanced cross-correlation of dual-comb interaction, error analysis and comprehensive performance evaluation, the absolute distance measurement system with the capabilities of large range, high precision, no blind zone and real time measurement is constructed. This research is expected to facilitate improvement of our independent innovation of large-scale precision ranging and positioning technology, and it also has prominent practical significance for further developing the advanced manufacturing, aerospace and defense technology, and promoting metrological capability in domestic precision measurement field.

大量程高精度激光绝对测距是大型装备精密制造和空间精密测距定位的关键技术，也是先进制造业发展的基础之一。本项目提出了一种基于单腔双向飞秒光梳输出的平衡互相关大量程实时绝对测距方法；创新性地利用单个光纤环形腔产生双向飞秒光梳输出进而开展双光梳绝对测距，在双光梳干涉信号提取中引入光学平衡互相关技术，并结合飞行时间测距和DSP并行信号处理技术，在降低系统成本同时将提升双光梳测距的量程、精度、抗干扰和实时测量能力。通过研究单腔双向飞秒光梳的发生机理及稳频机制、单腔双光梳脉冲相干性及其参数优化、双光梳平衡互相关绝对测距的理论模型、测量误差分析及性能综合评估等关键科学问题，构造大量程、高精度、可操作性强、更新速度快、无测量盲区的实时绝对测距系统。其研究成果将提高我国大尺寸精密测距和定位技术的自主创新能力，对进一步推动先进制造、航空航天、国防科技的发展以及提升我国的测试计量能力具有重要现实意义。

大量程高精度激光绝对测距是大型装备精密制造和空间精密测距定位的关键技术，也是先进制造业发展的基础之一。本项目提出了一种基于单腔双向飞秒光梳输出的平衡互相关大量程实时绝对测距方法，创新性地利用单个光纤环形腔产生双向飞秒光梳输出进而开展双光梳绝对测距，在双光梳干涉信号提取中引入光学平衡互相关技术，在降低系统复杂度的同时将提升双光梳测距的量程、精度、抗干扰和实时测量能力。围绕所提出的基于单腔双光梳实时绝对测距方法，项目开展了相关理论与关键科学问题研究，实现了单腔双光梳光源、测距光路、平衡互相关探测和快速信号处理模块的研制，搭建了单腔双向飞秒光梳测距系统，并开展了实时绝对测距实验和动态稳定性实验。实验结果表明：50μm范围内测距残余误差的峰峰值为353.3nm（-172.7nm～+180.6nm），标准差为102.3nm；基于PZT调制距离的动态实验发现系统可响应10nm调制幅度和几十Hz的调制频率，且平均时间为1s对应Allan方差结果优于100nm，证明了所搭建双光梳测距系统的高精度、良好测距稳定性和更新速度、无测量盲区等性能。同时，为了后续大量程测距比对，研究并搭建了基于飞秒光梳的多波长干涉实时绝对测距系统，实验室测量环境下的绝对测距非模糊度量程可达到几十米，2m线性位移内的测量精度达到36nm，相对测距精度达到10-8量级，下一步可直接用于与双光梳测距系统扩展量程后的长距离比对。项目研究成果及其技术可初步形成新的大量程高精度绝对测距技术原型，将提升我国大尺寸精密测距和定位技术的自主创新能力，并有望直接用于大装备制造、纳米精密工程和星间链路测距等领域，对进一步推动先进制造、航空航天以及提升我国的测试计量能力具有重要意义。