High mechanical resistant fiber Bragg gratings fabricated by CW UV laser irradiation

The issue of mechanical resistance of optical fibers irradiated by UV laser sources has been recently reported. An important mechanical degradation as expressed by the decrease of median breaking strength and the widening of the Weibull distribution has been observed after homogenous irradiation by pulsed laser sources. In contrary, CW UV laser irradiation showed considerably better results exhibiting median breaking strengths and m-values very close to that of pristine fiber. The effect has an important impact on the fabrication of all-fiber filters such as Bragg and long period gratings. In this paper we report the fabrication of high mechanical resistant Bragg gratings using a CW frequency doubled Ar/sup +/ laser.