光子带隙光纤陀螺纤芯异变致非互易误差研究

Photonic bandgap fiber optical gyroscope (PBFOG) is a novel fiber optical gyroscope (FOG) based on photonic bandgap fiber (PBF) and internationally considered as the next-generation FOG, having characteristics of low sensitivity to temperature, magnetic, radiation and so on. While PBF is significantly improving environment adaptability for FOG, the inevitable core aberrance exists during the process of PBF fabrication and its application in a FOG, thus causing strong forward and backward parasitic secondary waves. The interference among those secondary, primary waves causes core-aberrance-induced nonreciprocity (CAIN) error, and affects PBFOG performance and its development. In the research, the mechanism of the core-aberrance-induced forward and backward secondary waves in PBFOG is investigated, and their experienced information including optical path, modulation is tracked. Based on this, the mechanism of CAIN error is disclosed, as well as its influence on bias stability, scale factor nonlinearity and angle random walk in PBFOG, and suppression method is promoted from two levels of PBF and PBFOG, and from two aspects of amplitude and phase, in order to make PBF not deteriorate other performance in PBFOG while it significantly improves environment adaptability. Therefore, the research provides theoretical foundation for improving the next-generation FOG performance and making it have practical application as soon as possible.

光子带隙光纤陀螺是一种基于光子带隙光纤的新型光纤陀螺，具有低的温度、磁、辐照等环境敏感性，是国际公认的下一代光纤陀螺。光子带隙光纤在极大程度提高陀螺环境适应性的同时，其在拉制过程和应用于陀螺过程中不可避免的纤芯异变会带来强烈的前向、后向寄生次波，这些次波、主波之间相互干涉产生纤芯异变致非互易（CAIN）误差，劣化了光子带隙光纤陀螺性能，阻碍着光子带隙光纤陀螺的发展。本课题针对光子带隙光纤陀螺，明确基于纤芯异变的前向、后向寄生次波产生机制，追溯主要寄生次波在陀螺中历经的光程、调制等信息，从根源上揭示CAIN误差机理，及其对陀螺偏置稳定性、标度非线性和角随机游走的影响，从光子带隙光纤和陀螺两个层面，从幅值和相位两个角度提出CAIN误差抑制方法，并测试验证，使光子带隙光纤在发挥环境适应性优势的同时尽可能不劣化陀螺其他性能，从而为下一代光纤陀螺性能的完善以尽快实际应用奠定理论基础。

光子带隙光纤陀螺是一种基于光子带隙光纤的新型光纤陀螺，具有低的温度、磁、辐照等环境敏感性，是国际公认的下一代光纤陀螺。光子带隙光纤在极大程度提高陀螺环境适应性的同时，其纤芯异变会带来强烈的前向、后向寄生次波，这些次波、主波之间相互干涉产生纤芯异变致非互易（CAIN）误差，劣化了光子带隙光纤陀螺性能，阻碍着其发展。本课题针对光子带隙光纤陀螺，明确了陀螺中纤芯椭圆度、折射率变化、内壁粗糙度等导致的前后向寄生次波产生机制，提出了基于马赫曾德与迈克尔逊混合型干涉仪的寄生次波测试方法，揭示了CAIN误差机理，以及对陀螺偏置稳定性、标度非线性和角随机游走的影响，通过斜切熔接以减小次波幅值，匹配器件尾纤和消偏器长度以优化次波相位从而抑制CAIN误差，提出了利用调制相位变化产生的周期信息实现CAIN误差定量测试方法，并搭建了测试装置，研制了空芯光子带隙光纤陀螺样机，其零偏稳定性达到~0.4º/h，从而为光子带隙光纤陀螺性能的完善以满足恶劣工作环境下迫切需求奠定了基础。