Nonlinear group delay using asymmetric chirped gratings written in fibers under pre-stretched conditions

Abstract

We report a novel fabrication method to generate continuous chirp in a fiber Bragg grating using a uniform phase mask. The fiber is stretched before the grating is written. The stretched length of the fiber is varied while scanning the UV beam. The grating fabricated with this method has a nonlinear group delay response and an asymmetric passband spectrum. The analytical results agree with those obtained from experiments.