Photosensitivity and grating recording in all-silica standard and microstructured optical fibres using 248nm, fs and ps laser radiation

This paper presents the photosensitivity and Bragg grating inscription in all-silica standard and microstructured optical fibres utilising 248 nm, 5 ps and 500 fs laser radiation. The all-silica fibers exposed, were the fluorine depressed cladding Z- fiber, fabricated by Sumitomo, the micro-structured, endlessly single-mode fibres ESM-12-01, fabricated by former Blazephotonics and the LMA-10 fabricated by crystal fiber. The detailed investigation of the grating recording process by means of average and modulated refractive index changes; as well as, the thermal durability of the inscribed structures. The experimental results obtained for the hydrogenated fluorine-depressed cladding fibres indicate that the photosensitivity process occurs for those fibres is of single-photon nature; while for the pristine fibres exposed the underlying photosensitivity mechanism is that of two-photon absorption. The energy density dissipation into the fibre complex and the core area for the standard and microstructured optical fibres, were simulated utilising finite difference time domain method and results will be presented and discussed with respect to the photosensitivity process.