Characterization and optimization of photonic crystal fibers for enhanced soliton self-frequency shift

Modeling of the soliton self-frequency shift (SSFS) using the generalized nonlinear Schrodinger equation (GNLSE) is computationally intensive and becomes time consuming, particularly when comparing the self-frequency shift of several fibers. We present a simple theory that combines fission of a higher-order soliton with the Gordon equation for the evolution of a fundamental soliton. The theory allows the computation of the final soliton wavelength using a simple integration that is far less time consuming than solving the full GNLSE. In the simplest version of the theory no integration is even required. This approach was applied to compare the SSFS in photonic crystal fibers with different dispersion and nonlinear parameters, and the fiber that exhibited the maximum SSFS was selected. Findings of the theory were confirmed with full-scale simulations of the modified GNLSE and with experiments showing that the theoretically predicted fiber optimizes the self-frequency shift. (C) 2010 Optical Society of America