A Single-Polarization Single-Mode Photonic Crystal Fiber with Four Lines of Small Elliptical Air-Holes

Abstract

We present a novel single-polarization single-mode photonic crystal fiber (SPSM-PCF) design with four lines of small elliptical air-holes in order to obtain wider bandwidth for SPSM operation. The characteristics of the proposed SPSM-PCF are studied by using a full-vector finite element method (FEM) with perfect matched layer (PML) boundary conditions. At the wavelength of 1.55 µm, the confinement loss of the x-polarized mode is lower than 0.5 dB/km, whereas the loss of the y-polarized mode is larger than 50 dB/km. Compared with the case of x-polarized mode, the y-polarized mode can be suppressed in the PCF. Then, the SPSM operation is obtained. The proposed PCF can perform SPSM operation with broadband of 600 nm for considering the confinement loss ratio and the loss difference.