Ultrashort Pulse Reflection through Nonlinear Fiber Bragg Gratings

We discuss numerical studies of reflection of an ultrashort pulse (1 ps) through 10 mm length nonlinear fiber Bragg gratings (NLFBG). The ultrashort pulse is a Gaussian function centered in the Bragg wavelength for low input intensities: lambda₀ = 1550 nm. We used an inverse Fourier transform method never used before for nonlinear gratings to investigate the reflected time shapes. We determined how the nonlinear index affects the reflection responses for NLFBG´s and subsequently its pulse reflection shapes. It was found that the nonlinear switching depends on nonlinear strength of grating.