Ultrahigh effective mode area photonic crystal fibers with extremely low bending loss for long distance transmission application

Abstract

In this work, an extremely large mode area (LMA) photonic crystal fiber (PCF) design has been proposed having single mode operation. A full-vectorial finite element method (FEM) approach is considered with perfectly matched layer (PML) boundary for hybrid cladding with fluorine-doped silica holes in the cladding. An ultrahigh effective mode area can be achieved along with maintaining robust single mode operation. The hybrid cladding structure of the fiber makes it possible to exhibit lower bending loss and confinement loss. The proposed PCF design achieves an effective mode area of $1727.55\mu m^2$ at straight state and $719.08\mu m^2$ at bending state for a radius of $30\mathrm{cm}$ at a wavelength of $1550\mathrm{nm}$. The proposed fiber also exhibits both an extremely low confinement loss of $4.745\times {10}^{-4}\mathrm{dB}/\mathrm{Km}$ and a bending loss of $6.11\times {10}^{-4}\mathrm{dB}/\mathrm{Km}$ at $30\mathrm{cm}$ of bending radius at $1550\mathrm{nm}$ wavelength. Moreover, the ultrahigh effective area of the fiber makes it possible to obtain an ultralower non-linear coefficient.