Polarization properties of long-period gratings prepared by high-intensity femtosecond 352-nm pulses

We inscribed long-period gratings in a hydrogenated single-mode fiber (SMF-28) by high-intensity femtosecond near-ultraviolet pulses via a three-photon absorption mechanism. Due to energy deposition in the fiber cladding, such gratings are similar to those fabricated by CO/sub 2/ laser induced heating, mechanical pressure, or electric arc. We found that these gratings exhibit significant polarization properties.