The effect of CO<sub>2</sub> laser irradiation on the refractive-index change in optical fibers is investigated by measuring the interference fringe shift formed by a long-period fiber grating pair. The refractive-index decrease on CO<sub>2</sub> laser irradiation was due to relaxation of the residual stress, which was formed in optical fibers during the drawing process, and the refractive-index decrease was found to increase linearly with the drawing force. The effect of the CO<sub>2</sub> laser output power on residual-stress relaxation, and fiber elongation was also studied.
© 2002 Optical Society of America
Bok Hyeon Kim, Tae-Jung Ahn, Dug Young Kim, Byeong Ha Lee, Youngjoo Chung, Un-Chul Paek, and Won-Taek Han, "Effect of CO2 Laser Irradiation on the Refractive-Index Change in Optical Fibers," Appl. Opt. 41, 3809-3815 (2002)