A genetic algorithm based approach to fiber design for high coherence and large bandwidth supercontinuum generation

We present a new approach to the design of optical microstructured fibers that have group velocity dispersion (GVD) and effective nonlinear coefficient (gamma) tailored for supercontinuum (SC) generation. This hybrid approach combines a genetic algorithm (GA) with pulse propagation modeling, but without include it into the GA loop, to allow the efficient design of fibers that are capable of generating highly coherent and large bandwidth SC in the mid-infrared (Mid-IR) spectrum. To the best of our knowledge, this is the first use of a GA to design fiber for SC generation. We investigate the robustness of these fiber designs to variation in the fiber's structural parameters. The optimized fiber structure based on a type of tellurite glass (70TeO(2) - 10Na(2)O - 20ZnF(2)) is predicted to have near-zero group velocity dispersion (< +/- 2ps/nm/km) from 2 to 3 mu m, and a effective nonlinear coefficient of gamma approximate to 174W(-1) km(-1) at 2 mu m. The SC output of this fiber shows a significant bandwidth and coherence increase compare to a fiber with a single zero group velocity dispersion wavelength at 2 mu m. (C) 2009 Optical Society of America