We report on permanent refractive-index changes as great as 6 × 10<sup>−3</sup> in standard fibers on irradiation with tightly focused femtosecond (120-fs) near-IR (λ = 800-nm) pulses. The refractive-index increase was measured through changes in the transmission spectrum of an UV photowritten Bragg-grating-based Fabry–Perot interferometer. We depict the dependence of the index variation on exposure time. The changes in refractive index can be optimized after a few seconds of irradiation. The measured induced excess loss increases during near-IR exposure.
© 2001 Optical Society of America
(130.3120) Integrated optics : Integrated optics devices
(140.7090) Lasers and laser optics : Ultrafast lasers
(160.2290) Materials : Fiber materials
(190.4180) Nonlinear optics : Multiphoton processes
(230.1480) Optical devices : Bragg reflectors
Eric Fertein, Christophe Przygodzki, Hervé Delbarre, Arif Hidayat, Marc Douay, and Pierre Niay, "Refractive-Index Changes of Standard Telecommunication Fiber through Exposure to Femtosecond Laser Pulses at 810 cm," Appl. Opt. 40, 3506-3508 (2001)