Long-period fiber gratings written in the microstructure specialty fibers

摘要

We demonstrate the fabrication of long-period fiber gratings (LPFGs) written by CO2 laser in different micro-structure specialty fibers. The characteristics of grating growth were studied by using the dynamic analysis of laser writing process. It can be believed that the residual stress relaxation, glass structure changes, and frozen of the non-uniformed external stress account for the formation of LPFGs. The sensing characteristics of the LPFGs were investigated experimentally before and after nano-film coating of the gratings.