Highly Birefringent Elliptical-Hole Photonic Crystal Fiber With Two Big Circular Air Holes Adjacent to the Core

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In this letter, we propose a novel design for a polarization -maintaining index-guiding photonic crystal fiber (PCF). It is composed of a solid silica core, two big circular air holes near the core, and a cladding with elliptical air holes. Using a full-vector finite-element method, we study the modal birefringence of the fundamental mode in such a PCF. The numerical result shows that very high modal birefringence with magnitude of order of <formula formulatype="inline"> <tex>$10^{ - 3}$</tex></formula> has been obtained, which are higher than the birefringence induced by adding two big air holes near the core or using elliptical air holes in cladding separately. </para>