Birefringence induced by irregular structure in photonic crystal fiber

In-Kag Hwang,Yong-Hee Lee,Yong-Jae Lee

doi:10.1364/oe.11.002799

Abstract

The unintentional birefringence induced by the irregular structure in photonic crystal fibers is analyzed numerically using the plane wave expansion method. The statistical correlations between the birefringence and the various irregularities are obtained. The birefringence is found to be largely dependent on the fiber design parameters as well as the degree of the irregularity. And the large pitch and the small air hole make the fiber less sensitive to the structural irregularity, which is successfully explained by the simple perturbation theory. The accuracy of our analyses is confirmed by the detailed investigation of computational errors. This study provides the essential information for the characterization and the design of low birefringence photonic crystal fibers.

Highlights

The photonic crystal fibers (PCFs) have drawn great attention as the new waveguides with novel optical properties such as endlessly single mode operation [1], anomalous group velocity dispersion [2], and large effective core area [3]
The birefringence due to the structural irregularity in the PCF is extensively investigated by numerical analyses
The statistical correlations between the birefringence and the degree of the irregularity are obtained, and their behaviors are explained by the simple perturbation theory

Summary

Introduction

The photonic crystal fibers (PCFs) have drawn great attention as the new waveguides with novel optical properties such as endlessly single mode operation [1], anomalous group velocity dispersion [2], and large effective core area [3]. Their polarization characteristics have been widely investigated. High birefringence PCFs preserving polarization states were successfully developed by introducing highly asymmetric fiber structures [4,5]. The effective structure of the low birefringence PCF is proposed

Numerical birefringence of the perfect PCF

Birefringence of the PCFs with irregular structures

Design for low birefringence fibers

Conclusion