Azimuth angle orientation by side scattering for side-polishing of photonic crystal fibers

Abstract

We propose and demonstrate a nondestructive and contamination-free method for azimuth angle orientation of the photonic crystal fiber (PCF) and its application for fiber side-polishing. This technique is based on the interference pattern analysis of the light forward-scattered from the PCF that is side illuminated by a laser beam. The scattering pattern is analyzed by introducing a characteristic value which is the sum over the intensities of the upper-half or lower-half regions of the scattering pattern. The characteristic value correlates closely with the azimuth angle of PCF, which enables characterizing the azimuth angle through scattering pattern analysis. Three kinds of PCFs are studied for the determination of their azimuth angles, and an angular accuracy better than 0.5° is obtained. This method is subsequently applied to orient the angular azimuth in side-polishing of the PCF, and the accuracy of polishing angle is about 0.5°. This technique is nondestructive, contamination-free, easy to implement, and able to serve for in-line angular orientation during the fabrication of PCF-based optical devices and manipulation of the PCF.