利用宽谱光源及偏光干涉测量保偏光纤拍长

提出了一种用宽谱光源及偏光干涉效应测量保偏光纤拍长的新方法。利用光纤陀螺等光纤传感器常用的宽谱光源，以及2个性能一般的线偏振器件，与被测保偏光纤组成测试系统。宽谱光通过测试系统后，由于偏光干涉效应出现光谱形状的波动，波动周期受保偏光纤拍长的调制，通过调制周期可计算获得被测保偏光纤的拍长。该方法实验装置容易搭建，对偏振器件及操作精度的要求很低，对被测光纤的具体结构没有要求，任何保偏光纤的拍长都能测量，适用范围广，拍长测量精度可达0．1mm。

Measuring the Beatlength of Polarization Maintaining Fiber by Broadband Light Source and Conoscopic Interference

A new method to measure the beatlength of polarization maintaining fiber is shown. It utilizes the broadband light source and conoscopic interference phenomenon. The test system is composed of a broadband light source that is usually used in sensors such as the fiber optic gyroscope, two linear polarizers and the measured polarization maintaining fiber. After passing through the test system ,the shape of the broadband light spectrum will be modulated by the beatlength of fiber and becomes fluctuant. And as a result,the beatlength can be calculated by the modulation period. The measurement system is easy to be built up,and there is no strict demand on the operation precision and the polarizer performance. Any kinds of polarization maintaining fiber can be tested by the system. The measurement precision of the beatlength can be higher than 0. 1 mm.