Random period arc-induced long-period fiber gratings

Abstract

We report the fabrication of arc-induced long-period fiber gratings with strong random variations in the period. Long-period fiber gratings with standard deviations in the period from 8.50 to 36.98 μm were fabricated. The spectral position of the resonant bands is determined by the average period value, being similar to that observed in a long-period fiber grating with a fixed period equal to the average period of the random grating. Moreover the notch bands keep the shape characteristics like wideband and depth compared with a long-period grating with a constant period. In addition, their sensitivity to external parameters such as ambient refractive index is not too different with that of fixed period long-period gratings.