Bragg solitons in the nonlinear Schrödinger limit: experiment and theory

We present a detailed experimental and theoretical study of nonlinear pulse propagation in an apodized fiber Bragg grating. In particular, we consider the generation and the propagation of Bragg solitons with a frequency content just outside the grating’s photonic bandgap, where, thanks to the apodization, the transmissivity of the grating is high and the strong grating dispersion dominates. We demonstrate the efficient launching of Bragg solitons with velocities as low as 50% of that in untreated fiber. The experimental results agree well with numerical simulations obtained by solving the full nonlinear coupled-mode equations that govern the experimental geometry. We also show that, for most parameters, the experimental results are in very good agreement with a nonlinear-Schrödinger-equation model. Thus many of the results known for the nonlinear Schrödinger equation can be brought to bear on our results.