Fabrication of fiber Bragg grating by femtosecond laser interferometry

The aim of this study is to fabricate and evaluate the transmission and reflection of FBGs induced by focused femtosecond laser interferometry. The two beams are focused inside the core, and the colliding angle is set in order to obtain an 2nd order Bragg reflection at around 1.45 /spl mu/m. The laser output power is varied using attenuators and adjusted not to reach the optical breakdown threshold at the focal spot. The transmission spectrum is examined simultaneously as the fabrication process is executed. The reflection spectrum is analyzed after fabrication has been completed.