By use of high-intensity (Ϸ200 GW/cm 2) femtosecond 264-nm laser light and a phase mask technique, Bragg grating inscription in a range of different photosensitive and standard telecom fibers (both H 2-free and H 2-loaded) was studied. The dependences of the induced refractive index modulation versus the incident fluence as well as the thermal decay curves were compared with similar dependences for gratings fabricated by other existing methods. It was shown that with high-intensity UV laser irradiation, two-quantum photoreactions occur in the irradiated fiber core, that result in a significant photosensitivity enhancement of the investigated fibers in comparison with conventional low-intensity 248-nm exposure (by 6-128 times, depending on fiber type and irradiation intensity).

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We demonstrate UV poling of a pure fused silica sample by applying to it an electric field of 200 kV/cm and irradiating it with high-intensity (similar to40 GW/cm(2)) femtosecond (220 fs) laser pulses at 264 nm. (C) 2005 American Institute of Physics. (DOI:10.1063/1.1868075