Strong long-period fiber gratings recorded at 352 nm

We describe long-period grating inscription in hydrogenated telecom fibers by use of high-intensity femtosecond 352 nm laser pulses. We show that this technique allows us to fabricate high-quality 30 dB gratings of 300 mu m period and 2 cm length by use of a three-photon absorption mechanism. (c) 2005 Optical Society of America.