Abstract
Photosensitivity in a perfluoropolymer (CYTOP) optical fibre is investigated. Significant diffraction has been observed from transmission gratings made from the fibre. A maximum diffraction efficiency of 1.6% has been achieved, corresponding to an index change ~= 3 × 10-4. This study demonstrates for the first time the existence of significant photosensitivity and the feasibility of writing Bragg grating in CYTOP fibres.