Numerical analysis of aperiodic photonic crystal fiber structures for supercontinuum generation

An unconventional photonic crystal fiber (PCF) is designed in order to obtain supercontinuum (SC) generation. The distance of the air hole rings is not constant, but it follows the Thue-Morse (ThMo) aperiodic sequence. The spectral broadening of high power femtosecond (fs) input pulses in anomalous dispersion regime is investigated by means of a homemade computer code, based on the generalized nonlinear Schrodinger equation (GNLSE) and implemented via the symmetrized split-step Fourier method (S-SSF). A lot of ThMo PCF transversal sections are simulated, and the one providing the flattest and the widest spectrum is identified and further refined by varying the operating conditions. Three different peak powers (5, 10, 15 kW) and three different pulse durations (40, 50, 100 fs) are investigated at the pump wavelength lambda(P) = 1064 nm. The novel ThMo PCF proposed in this paper exhibits a SC figure of merit Phi = 16, very high with respect to the state of the art pertaining to fs input pulses. (C) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.OE.51.3.035003]