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Novel growth behaviors of fiber Bragg gratings in polymer optical fiber under UV irradiation with low power

Some novel behaviors in fiber Bragg gratings (FBGs) growth have been observed when the polymer optical fiber are exposed to low-power level of ultraviolet (UV) irradiation. For the first time, we observed the growing and erasing of polymer FBGs under UV exposure, and regrowing after the UV exposure is off. The growth behaviors are quite different in contrast with the previously reported Type I and Type II polymer optical FBGs behaviors. This discloses that polymer FBG growth is a writing-power-dependent process.