Point-by-point writing of first and second order FBGs through polyimide coating with femtosecond radiation at 1026 nm
There are presented the results on femtosecond writing of first and second order fiber Bragg gratings (FBG) through protective plastic coating of a fiber. In particular, there were written uniform gratings in non-photosensitive fibers with polyimide coating: SMP1500(9/125)P and pure-silica core SMP1500SC(9/125)P, with the reflectance spectra which are in good agreement with calculation results. It was demonstrated that the method can be used for writing of superstructure FBGs.