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Bragg grating inscription with low pulse energy in doped microstructured polymer optical fibers

Min, R. ; Ortega, B. ; Nielsen, K. ; Bang, O. ; Marques, C.

IEEE Sensors Letters Vol. 2, Nº 2, pp. 1 - 4, June, 2018.

ISSN (print): 2475-1472
ISSN (online):

Journal Impact Factor: (in )

Digital Object Identifier: 10.1109/LSENS.2018.2830804

Abstract
We demonstrate that fiber Bragg gratings (FBGs) can be written in a doped polymer optical fiber (POF) in a low UV pulse energy regime (60 µJ/pulse) using a 248 nm krypton fluoride (KrF) excimer laser system. The total energy density per inscription necessary to obtain Bragg gratings is between 493.6 mJ/cm2 and 3825 mJ/cm2, depending on the number of pulses and the pulse energy. The impact of the pulse energy on the growth of the Bragg grating is investigated and it is shown that the 248 nm light induces a positive refractive index change. This paper demonstrates that FBGs can be obtained in POFs without high pulse energy (mJ level) at 248 nm wavelength, which reduces maintenance costs. Furthermore, we can consider it as a solution to increase the life time of the laser system without high energy still allowing
fast and efficient production of the FBGs for sensing applications.