Finite element characterisation of photonic crystal fibres
type: CreativeWork
description: Rigorous numerical simulations have been carried out by using the Finite Element Method (FEM) in order to calculate bending and leakage losses of Photonic Crystal Fibres (PCF). A modal solution approach including the implementations of the conformal transformation and the Perfectly Matched Layer (PML) were undertaken to determine the bending and leakage losses of several designs of Photonic Crystal Fibres. This was carried out by varying key parameters such as the pitch (Λ), diameter (d) and air-filling fraction (d/Λ). Output modal parameters including the effective indices, spot sizes, leakage and bending losses as well as the mode field profiles were obtained. These output parameters were obtained by varying the bending radius (R) from very large values to very low values for different dimensions of the PCF, with results being obtained for Transverse Magnetic and Transverse Electric (quasi-TM and quasi-TE) polarizations. These parameters were calculated by solving the Maxwell’s equations using the H-field vector formulation and with the inclusion of PML to solve complex eigenvalue equations. Generally, it was observed that for all Λ, d/Λ and the polarization considered, as R is reduced from a very high value to lower values, the bending losses increase and there is a sharp increase at some lower values of R. At some very low values of R, some oscillatory behaviour was observed in the curves obtained for the fibre losses, where further investigations were carried out. These oscillations appeared due to degeneration of the fundamental mode with the cladding modes. In most of the cases investigated, there was a correlation in the variation of effective indices the loss values and also in the variation of spot sizes. PCFs with non-identical air-holes were also investigated in which case the d ≠ d2 (diameter of 4 larger air-holes in the first ring) and knowing the values for TM and TE polarizations, it was possible to determine the birefringence, which is the differenc…
abstract: Rigorous numerical simulations have been carried out by using the Finite Element Method (FEM) in order to calculate bending and leakage losses of Photonic Crystal Fibres (PCF). A modal solution approach including the implementations of the conformal transformation and the Perfectly Matched Layer (PML) were undertaken to determine the bending and leakage losses of several designs of Photonic Crystal Fibres. This was carried out by varying key parameters such as the pitch (Λ), diameter (d) and air-filling fraction (d/Λ). Output modal parameters including the effective indices, spot sizes, leakage and bending losses as well as the mode field profiles were obtained. These output parameters were obtained by varying the bending radius (R) from very large values to very low values for different dimensions of the PCF, with results being obtained for Transverse Magnetic and Transverse Electric (quasi-TM and quasi-TE) polarizations. These parameters were calculated by solving the Maxwell’s equations using the H-field vector formulation and with the inclusion of PML to solve complex eigenvalue equations. Generally, it was observed that for all Λ, d/Λ and the polarization considered, as R is reduced from a very high value to lower values, the bending losses increase and there is a sharp increase at some lower values of R. At some very low values of R, some oscillatory behaviour was observed in the curves obtained for the fibre losses, where further investigations were carried out. These oscillations appeared due to degeneration of the fundamental mode with the cladding modes. In most of the cases investigated, there was a correlation in the variation of effective indices the loss values and also in the variation of spot sizes. PCFs with non-identical air-holes were also investigated in which case the d ≠ d2 (diameter of 4 larger air-holes in the first ring) and knowing the values for TM and TE polarizations, it was possible to determine the birefringence, which is the differenc…
author: Uthman, Muhammad
keywords: TA Engineering (General). Civil engineering (General)
date published: 2013
date modified: 2026-07-24T01:38:58Z
provider: City University of London
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: City University London