Outside Vapour Deposition process was used to demonstrate transparent and defect-free optical preforms on a wide range of glass compositions. Fabrication parameters were established for deposition, dehydration and consolidation of optical preforms using a thermodynamic analysis. Also, the drawing conditions for canes and fibres were stablished. Silica depositions were demonstrated for applications on high quality substrates or jacketing material. Fluorine-doped silica glass was fabricated with a refractive index of -6 ×10^-3 below pure silica level. A wide range of germanium-doped silica preforms were fabricated from 5-95%. Optical fibres ranging from SMF-like profile to a high NA and small core fibre were fabricated. 100% Germania deposition was successfully achieved and consolidated. 100% germania core rods were inserted into pure silica substrate and an ultra-high NA pre-form and fibre was achieved. A fibre Bragg grating was inscribed showing the multimode properties of this high NA fibre. Crystallisation study was carried out for Germanosilicate glasses. Aluminosilicate glass preforms were achieved via traditional and modified solution doping. Concentrations of ~20,000ppm or rare-earth ions were achieved. Large core fibres were fabricated with a small NA. Phosphosilicate glass was successfully demonstrated on passive and active preforms. Refractive index shows an ultra large core with a refractive index difference of 0.01. Co-doped germanium and phosphorous glass was successfully achieved on preforms with refractive index difference of ~0.01. Stimulated emission measurements demonstrate the successful incorporation of RE-ions into both aluminosilicate and phosphosilicate preforms showing the distribution of the dopant.