FBG inscription in non-hydrogenated SMF28 fiber with a ns Q-switched Nd:VO4 laser at 213 nm

Fiber Bragg grating (FBG) inscription efficiencies with a nanosecond (ns) KrF-Excimer laser source at 248 nm and with a ns Q-switched, 5 th -harmonic Nd:VO 4 laser source at 213 nm were compared. With both laser sources the phase mask method was used for FBG inscription. The growth process of the refractive index change during UV-exposure is presented as a function of cumulated fluence for inscription in standard non-hydrogenated SMF28 fibers. The inscription efficiency was found to be significantly higher for the 213 nm than for the 248 nm radiation, indicating a higher photosensitivity at 213 nm compared to 248 nm in low Ge-doped fibers.