This work encompasses characterisation of defects and dosimetric studies of novelrntailor made doped SiO2 fibres. Present studies have been carried out seeking to improve uponrnthe thermoluminescence (TL) yield of commercially produced small diameterrntelecommunication optical fibres. Using the modified chemical vapour deposition (MCVD)rnprocess, the optical fibres have been fabricated to a range of dopant concentrations of nominalrnvalue 6- 8- and 10 wt%. In this study, three different types of optical fibres have been utilised,rnmade using the same doped preform. The doped fibres are cylindrical fibres (CF), flat fibresrn(FF) and photonic crystal fibres (PCF). It should be noted that the process of fibre drawing hasrnbeen found to produce defect centres, influencing characteristics of optical fibre and TLrnresponse. To seek support of this, an X-ray Photoelectron Spectroscopy (XPS) study of a GedopedrnSiO2 fibres sample has been undertaken to determine the oxidation state of Ge. Resultsrnfrom this have confirmed the efficiency of the surface analysis technique, leading tornunderstanding of the Ge structure. Following on from this, facilities supporting characterizationrnof the fibres are outlined, including an ion beam facility used for Particle Induced X-rayrnEmission (PIXE)/Rutherford Back Scattering (RBS) analysis to localize and determine thernconcentration of Ge dopants. Building upon these characterisations, thermoluminescence studiesrnwere carried out. For the first of the experiment, undoped flat fibres were used, comparison ofrnresponse being made with that of conventional TLD-100 and commercial Ge-doped silicarnfibres. The undoped flat fibres provide competitive TL yield to that of TLD-100, being somern100 times that of the Ge-doped fibres. Pt-coated flat fibres have then been used to increase thernphotoelectron production and hence local dose deposition, obtaining significant increase in dosernsensitivity over that of undoped flat fibres. Using 250 kVp X-ray beams, the TL yield reveals arnprogressive linear increase in dose for Pt thicknesses from 20 nm up to 80 nm. Finally, tornillustrate the potential of novel tailor-made doped SiO2 optical fibres, the dosimetricrncharacteristics that have been investigated include, dose response, glow curves and energyrndependence. Taking TLD-100 as a benchmark, results are presented for Ge-doped, Ge-B-dopedrnand Ge-Br-doped optical fibres. The dose response of doped silica fibres was found to be linearrnover the range 2 cGy up to 50 Gy, also showing good dosimetric response for low photonrnenergies. Additional investigation of the same doped SiO2 optical fibres have been conductedrnfor measurement of TL yield from the high linear energy transfer (LET) radiation offered by arnliquid 223Ra alpha particle source.