【作者】 张春慧；

【导师】 谢洪波；

【作者基本信息】 天津大学 ， 光学工程， 2007， 硕士

【摘要】 陀螺作为指示方位角的重要传感器,在导航、制导、卫星定位、大地测量、天文望远镜跟踪、机器人运动、高级汽车导向等军用和民用诸多方面起着极为关键的作用。基于Sagnac效应的干涉型光纤陀螺由于其质量轻、尺寸小、精度高、寿命长、无运动部件而成为国际上研究开发的最重要的光纤传感器之一。干涉型光纤陀螺分为保偏型(PM-FOG)和消偏型(D-FOG)两种,前者采用全保偏光纤,通过保持光纤中光偏振态的稳定性,来抑制偏振态变化引起的输出漂移,因而精度高,成本高;消偏型光纤陀螺是在单模线圈陀螺中采用消偏器,使光路中光强在偏振轴各个方向上的分布均匀,进而减小陀螺漂移,提高精度。由于全保偏方案使陀螺成本大大提高,而消偏方案对陀螺成本影响不大,所以,消偏型光纤陀螺在中低精度,低成本的光纤陀螺应用领域中具有广阔的发展前景。本课题旨在研制面向民用市场的低成本,中低精度的消偏型光纤陀螺。论文首先介绍了光纤陀螺的原理及其在国内外发展情况,其次对保偏光纤陀螺和消偏光纤陀螺光路结构以及其系统中的各光电器件进行了理论分析。接下来利用琼斯矩阵分别构建了保偏和理想情况下双消偏光纤陀螺系统的的光路数学模型,并在此基础上完成了非理想情况下双消偏陀螺系统的光路数学模型及其各个指标参数的推导计算。最后,从理论上对消偏陀螺的重要元件消偏器的两种结构进行了分析及计算,并在实验中完成了两种消偏器的制作及其性能测试,得到了满足本课题要求的Lyot消偏器的结果。另外,本文通过对消偏系统中两个消偏器的长度进行特殊设置,成倍降低了单模线圈双折射效应的影响;通过实验验证分析了利用单根保偏光纤的双折射延迟效应,将不同波长的光旋转到不同的偏振状态,从而实现消偏的特殊消偏器结构;通过理论推导,构造了使用环形器替代耦合器的消偏光纤陀螺结构,该结构在降低对SLD光源要求的同时,提高了系统。更多还原

【Abstract】 Gyroscope, as a major sensor in acquiring azimuth angle, plays an important role in both civil use and military use, such as guide for navigation, satellite position finding, geodetic surveying, astronomical telescope tracking, robotic motion and automobile navigation. The interferometric fiber optic gyroscope(FOG) based on Sagnac effect has became to one of the most important fiber sensor in developing due to light in quality, compact in dimension, high accuracy and long life. The interferometric FOG can be divided into two categories, PM-FOG and D-FOG, the former one employs polarization-maintaining fiber, which rejects the output drifting induced by variation of polarization state by means of keeping the stability of polarization state in fiber optic, hence, results in high accuracy and high cost; D-FOG uses depolarizer in single mode fiber, which can uniform light intensity on each axis of polarization, in order to minimize drifting of FOG and increase accuracy. Comparing to D-FOG, using PM-FOG would increase the costs dramatically, so D-FOG has a bright future in cost efficiency and low accurate FOG area.The objective of this project is to develop D-FOG, which is cost efficiency, low accurate and mainly for civil use. Firstly, the author reviewed the basic principle of FOG and the literature about FOG, and also introduced the photo-conducting devices in use of the PM-FOG and D-FOG. Secondly, for both polarization-maintaining system and ideal dual depolarizing system, mathematical model of optical paths were built separately using Jones matrix, and mathematical model of optical paths in un-ideal dual depolarizing FOG system was completed, so was deducing and calculating several parameters. At last, two different structures of depolarizer, key device of D-FOG, were analyzed and calculated theoretically. Manufacture and testing of two kinds of depolarizers was completed by means of experiments, and the result of testing Lyot depolarizer, which was used in this project, was acquired.Bsides, in this project the length is distinguishingly set to reduce the effect of birefringence in SM optical fiber and the single PM optical fiber depolarizer was testified by experiment, the optical circulator is also proved can take place of optical coupler.更多还原