Thermoluminescence Evidence for Laser Induced Crystallisation of Tm Doped Germanosilicate Fibres

Abstract

Laser illumination of optical fibres can modify the refractive index of germano-silicate fibres and introduce optical non-linearity. New luminescence data not only confirm that the laser treatments are wavelength specific, but also the defect structures are altered. Low temperature thermoluminescence of fibres, previously illuminated at 476 nm, gives a glow peak of <2 K width, which is interpreted as evidence of a transition between laser induced crystalline phases.