Determine The Azimuth Angle Of Photonic Crystal Fibers By Analyzing The Characteristics Of Forward Scattering Patterns

In order to meet the requirement of determining the azimuth angles in fabricating optical devices from photonic crystal fibers(PCFs), a method based on analyzing the forward scattering patterns has been proposed. The scattering light is generated when laser is transversely illuminating a photonic crystal fiber. We analysed the forward scattering pattern respectively in the experiment and simulation.Firstly, the experiment system design was introduced, and the optical simulation software COMSOL was used to simulate the phenomenon of scattering light when laser transversely illuminating a photonic crystal fiber. According to analysis of the forward scattering pattern, we found that the electric field norm of the center of the scattered pattern, the forward scattering pattern is divided into the upper and lower part which calculate the summary the electric field norm of total each part, the electric field norm of total forward scattering pattern, can be used to determine the azimuth angle of photonic crystal fiber.Secondly, The PCF sample was illuminated transversely by 650 nm laser, the forward scattering patterns and the tip microscopic images were simultaneously recorded. Comparing the simulation results and the experiment results, the sum of the forward scattering patterns as the characteristic values was used to analysis the azimuth angles of photonic crystal fibers. The characteristic values from half-images presents good correspondence to the azimuth angles of the photonic crystal fiber. Based on this correspondence the special azimuth angle can be determined. The accuracy(0.5°) obtained in the applications to three kinds of PCFs proved that the proposed method was effective and universal. Therefore, the method based on analyzing the characteristic values from half-images of scattering pattern can be used in determining the azimuth angle of photonic crystal fiber.At last, this method was used to determine the azimuth angle of other kinds of photonic crystal fibers with the accuracy of 0.5°. Then the scattering pattern characteristic method was applied in side-polish-fiber technology to polish the predetermined azimuth angle of photonic crystal fiber we needed.This non-destructive, non-contact, online, no pollution, simple process, and high precision method can be used to determine the azimuth angle of all kinds of photonic crystal fibers. And its application prospect is important In summary, this technologies have very important foreground of application in processing the photonic crystal fiber devices.The innovations of this paper are as follow:1. The analysis based on the simulation which was used to determine theazimuth angle of photonic crystal fiber was provided guidance forexperiment.2. The method can be used to determine the azimuth angle of photonic crystalfibers by analyzing the characteristics of forward scattering patterns.This method was used to determine the azimuth angle of other kinds ofphotonic crystal fibers, and the scattering pattern characteristic methodwas applied in side-polish-fiber technology to polish the predeterminedazimuth angle of photonic crystal fiber we needed.