Fibre Bragg grating fabrication

Imamura K, Nakai T, Sudo Y and Imada Y, High reliability of tin-codoped germanosilicate fibre Bragg gratings fabricated by direct writing method . Electron. Lett, 1998, 34(18), 1772-4. 

CW laser irradiation results in the mechanical resistance of a fibre being similar to that of a pristine fibre. This is in contrast to the case where the fibre undergoes pulse excimer irradiation. The total dose dependence is also less pronounced in the case of CW irradiation. This phenomenon has important consequences for Bragg grating fabrication, where high mechanical resistance is required for strain applications. 

The mechanisms responsible for the formation of periodic structures in polymers have been explained. " They can be classified into photolysis, oxidization and laser ablation for the surface relief gratings, while chain scission, cross-link and photopolymerization are considered to be responsible for bulk or volume gratings and in-fibre gratings. The cross-link in Bragg grating fabrication can be shown as ... 

Askins C C, Putnam M A, Williams G M and Friebele E J, Stepped-wavelength optical-fibre Bragg grating arrays fabricated in line on a draw tower . Opt. Lett., 1994,14, 823-4. 

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