Enhanced photosensitivity in germanosilicate fibres exposed to CO₂ laser radiation

• Main Authors: Brambilla, G. (Author), Pruneri, V. (Author), Reekie, L. (Author), Payne, D.N (Author)
• Format: Article
• Language: English
• Published: 1999.
• Subjects: Article
• Online Access: Get fulltext

We report a novel method to increase the UV photosensitivity of GeO₂:SiO₂ optical fibers based on exposure to CO₂ laser irradiation before grating writing. Fibers treated with a CO₂ laser can produce gratings with refractive-index modulation two times greater and a Bragg wavelength that can be 2 nm longer than those of untreated fibers. Experiments on GeO₂:SiO₂ preform samples treated with a CO₂ laser in a way similar to the fibers showed a marked increase of the 242 nm absorption band, which is associated with an increase of germanium oxygen-deficient centers and is believed to be responsible for the higher photorefractive response.