一种测量光学滤波器参数的低相干方法

在光纤通信网络中, 以微环为代表的光学滤波器是实现在波长频段选择功能的重要器件。测量该器件的物理参数不仅是实际应用的需求更有利于设计更加复杂的滤波器结构。本文基于低相干干涉测量技术, 给出一种通用数学方法, 可获得复杂结构微环滤波器的物理参数。该方法引入数字滤波器概念以及 Z变换分析法来对光学滤波器进行建模, 并用简洁的线性方程组将干涉图中峰值以及传输函数的系数关联起来。对于一个给定的滤波器结构, 根据传输函数与物理参数的内在关联, 物理参数就能被准确地计算出来, 从而为器件的激光修正提供关键参数。实验结果表明, 该方法实现了低成本并且准确可行。

A General Characterizing Method for Optical Filter Based on Low Coherence Measurement

Optical filters are crucial devices for wavelength channel selecting in WDM fiber-optic communication networks. To measure the inner physical parameters of optical filters is significant for analyzing emerging new and more complex structures. A general and easy-to-operate method is proposed to extract physical parameters for complex filter structures with optical low-coherence measurement. By treating optical filters with digital filter concepts and Z-transform analysis, we can build the relation between interferogram peak values and transfer function coefficients with brief linear equations. These equations can be used to derive the exact expression of transfer functions, which can manipulate the physical parameters. For a given filter structure, according to relations between transfer functions and physical parameters, the physical parameters could be extracted. This is especially meaningful in the post–fabrication process.