Investigation of long term stability of arc-induced gratings heat treated at high temperatures
G. Rego, P. Caldas, ESTG-IPVC - School of Technology and Management-Polytechnic Institute of Viana do Castelo (Portugal); O. Ivanov, Ulyanovsk Branch of Kotel’nikov Institute of Radio Engineering and Electronics of Russian Academy of Sciences (Russia); J. L. Santos, INESC Porto - Institute for Systems and Computers Engineering of Porto (Portugal)
A long-period grating written in the SMF-28 fiber was heat treated at 1000 ºC for 15 days. The spectrum of the grating shifted to longer wavelengths and the amplitude of the cladding mode resonances decreased as a result of structural relaxation. The background loss increased considerably for time longer than 200 h, and this loss is caused by devitrification of the fiber.
