Numerical Study of Highly Nonlinear Photonic Crystal Fiber with Tunable Zero Dispersion Wavelengths

摘要

Solid-core silica photonic crystal fiber is proposed borrowing the concept of golden ratio (1.618) and keeping it between pitch and air hole diameter Λ/d in a subset of six rings of air-holes with hexagonal arrangement. In the case when we have a pitch equal to one micron (Λ = 1 μm), we need air-holes diameters d = 0.618 μm in order to achieve two zero dispersion wavelength (ZDW) points at 725 nm and 1055 nm;this gives us the possibility to use the fiber for supercontinuum generation, by pumping close to that points, pulse compression or reshaping. We analyzed a series of fibers using this relation and showed the possibilities of tunable ZDW in a wide range of wavelengths from 725 nm to 2000 nm, with low losses and small effective area. In agreement with the ZDW point needed, the geometry of the structure can be modified to the point of having only three rings of air holes that surround the solid core with low losses and good confinement mode. The design proposed here is analyzed using the finite element method with perfectly matched layers, including the material dispersion directly into the model applying the Sellmeier’s equation.