光纤陀螺用Y分支光波导的质子交换及退火研究

【作者】 王帆；

【导师】 陈福深；

【作者基本信息】 电子科技大学 ， 光学工程， 2008， 硕士

【摘要】 Y分支是集成光学中的重要器件单元，广泛应用于调制器，光开关，光分路器的器件中，尤其是作为中高精度光纤陀螺系统的核心器件。首先，文章简要阐述了干涉式光纤陀螺仪(I-FOG)的基本工作原理；然后，利用有效折射率法，讨论得到高斯型渐变折射率波导在单模传输条件。在Y分支光波导的设计方面，针对两种不同弯曲Y分支的弯曲损耗，分别用光波导的弯曲损耗理论和时域有限差分光束传输法(FD-BPM)仿真，得出了一组最优化的Y分支光波导设计参数。然后结合扩散反应动力学理论中的空位与间隙扩散机制，分析了质子交换、退火质子交换、缓冲源质子交换波导的折射率变化。并对交换后铌酸锂波导的晶相特性进行分析，从晶体结构和H~+浓度的角度来解释其特性变化。对交换过程添加缓冲质子源(苯甲酸锂)从而导致表面扩散系数发生改变进行了理论分析。讨论了质子交换和退火工艺的原理及制作技术，利用常用工程解法对质子交换深度和交换时间等诸多因素影响下得到的结果进行了比较，提出先进行质子交换，期间加入少量苯甲酸锂，然后在一定条件的退火，这样可以缩短节省制作周期，得出生成α相波导的最佳工作条件。最后通过大量的试验和实际工艺制作，验证了前面的理论分析，得到了可工作的光波导片。然后进行精密光学测试，得到实验数据。最后通过讨论这些实验数据，得出Y分支波导的主要性能指标。更多还原

【Abstract】 Y branches is important in the integrated optical devices unit, it is widely used in modulator, optical switching, optical splitter devices, especially in high-precision FOG.First, this paper has introduced the development situation of the integrated optics, and discussed the basic theory of FOG.Then, using the method of effective refractive index, discussed single-mode transmission conditions in Gaussian graded index waveguide. To the design of the Y-branch optic waveguide bending loss, the pure bending loss theory and the finite difference beam propagation method（FD-BPM） are used to analyze two kinds of Y-branch with different S-shaped channel waveguide bends by Matlab and get the optimization of the Y-branch waveguide profile. At last, the designing parameters of phase modulator are given.In the aspects of the fabrication of Y-branch, the proliferation theory is introduced to explain the proton exchange and anneal technique. From the perspective of the concentration of H⁺ analysed The Crystal structure and refractive index distribution of proton exchange LiNbO₃ waveguide are analysed from the perspective of the concentration of H⁺.The Kinetics principle is introduced to study the change of diffusion coefficient when buffer proton source is used. By comparing the characteristics of annealing and buffer proton source waveguide, then the formation conditions ofα-waveguide is given.At last, the whole procedure of fabrication device is described. The main optic parameters of Y branch such as insertion loss, split ratio and polarization crosstalk are tested.更多还原