保偏光纤侧视成像光强分析及定轴方法研究

Light Intensity Analysis and Alignment Method for PM Fiber

保偏光纤偏振轴方位角的确定和调整对改善光纤器件性能有重要意义。为进一步提高定轴精度,国内科研人员在透镜放应侧视(POL)法的基础上提出了五点法、五指法等,其理论定轴精度有所提高。但由于此类方法是建立在特定光强分布的前提下,对成像面调节要求较高,因此其实用性受限。该文以保偏光纤侧视成像为基础,通过对保偏光纤不同成像面的侧视成像光强分布作了大量仿真分析发现,光纤旋转至慢轴与水平方向成0°角附近时,光强分布会发生明显变化,利用这一现象可对0°位置进行识别。因此,该文改变了以往通过寻找某特定光强分布进行定轴的思路,提出了通过对0°位置进行识别的定轴方法,该方法通过简单的图像处理和数据分析即可判断偏振轴的偏转情况,适用的成像面位置范围也相对更宽,可操作性强,实用前景好。

The determination and adjustment of the polarization axis azimuth of the polarization maintaining(PM)optical fiber is of great significance for improving the performance of the optical fiber devices.In order to further improve the accuracy of the aligning axis,the domestic researchers have put forward the five-point method and the five-finger method on the basis of the POL method,and the theoretical alignment accuracy has been improved.However,such methods are limited in practicability because they are based on the premise of specific light intensity distribution and the imaging plane adjustment requirements are high.Based on the side-view imaging of polarization-maintaining fiber,a large amount of simulation and analysis of the side-view imaging intensity distribution of different imaging planes of polarization-maintaining fiber have been carried out in this paper.It is found that when the fiber rotates to the vicinity of the slow axis at an angle of 0°to the horizontal direction,the light intensity distribution changes significantly.This phenomenon can be used to identify the 0°position.Therefore,this paper changes the previous idea of aligning the axis by finding a specific light intensity distribution axis,and proposes an alignment method to identify the 0°position.The method can determine the deflection of the polarization axis by simple image processing and data analysis.The applicable imaging plane position range is relatively wider,the operability is strong and the practical prospect is good.