New nanosecond Q-switched 213 and 224 nm lasers for fiber Bragg grating inscription in hydrogen-free fibers

摘要

In this paper, it is demonstrated for the first time to our knowledge the use of a novel high-repetition rate 224 nm nanosecond Q-switched laser source for fiber Bragg grating fabrication. Results are compared with 213 nm a nanosecond laser source, recently reported for grating inscription. High index change are rapidly obtained using a phase mask technique in B/Ge doped fiber with a maximum average writing power of only 280 mW at 224 nm and 100 mW at 213 nm. Strong gratings can also be written in standard SMF28 fiber. Photosensitivity is shown to be due to single and two-photon absorption for SMF28 and B/Ge doped fiber, respectively.