Fabrication and characterisation of aluminium doped silica fibre preform

This thesis describes the fabrication and characterisation of alumina-doped silica fiber preforms by the modified chemical vapour deposition (MCVD) method coupled with solution doping technique. The silica soot deposited at 1800°C was examined by scanning electron microscopy (SEM) and gas adsorption technique with BET in order to shed light on its characteristics such as morphology, surface area, porosity and pore size distribution. Three ethanolic solutions with concentrations of 0.3M, 0.7M and 1.2M were prepared using aluminium chloride hexahydrate and used for the solution doping process. In addition, for each Al solution concentration, a multiple-soaking solution doping process was used to incorporate higher amounts of Al2O3 into the silica glass network in order to achieve higher refractive indices and hence, higher numerical apertures of the final fibers