Numerical Analysis of an Ultra-High Negative Dispersion Compensating Micro-Structured Optical Fiber With Air-holes Arranged in Octagonal Structure

Abstract

In this paper, a high dispersion compensating photonic crystal fiber (PCF) has been proposed, fabricable with simple fabrication schemes. The lattice design structure is comprised of five rings of circular air-holes. The rings are arranged with an octagonal geometry. The fiber exhibits an ultra-high negative dispersion, that cancels the accumulated positive material and group velocity dispersion, such that the transmitted optical signal remains almost undistorted. The full vector finite element method (FEM) incorporated with a circular, perfectly matched layer (PML) at the boundary is implied to investigate the different optical properties of the proposed fiber. The numerical simulation of the designed fiber indicates that an ultra-high negative dispersion of -3112 ps.nm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> .km <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> at 1.55μm wavelength can be obtained, which can reduce the length of dispersion compensating fiber significantly. Besides, the structural diameter deviation of ±2% over the optimum value of the proposed PCF is evaluated for investigating fabrication flexibility. Moreover, the proposed fiber exhibits high nonlinearity of 94.89 W <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> km <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> at 1550 nm wavelength, which makes the proposed fiber a suitable candidate for optical back-propagation application, super-continuum generation, and high-bit-rate optical transmission system.