Characterization of self-phase modulation in liquid filled hollow core photonic bandgap fibers

We experimentally and theoretically study self-phase modulation by Kerr effect in a liquid filled hollow core photonic crystal fiber. We perform a complete characterization of the linear optical properties of the hollow core photonic bandgap fiber filled with deuterated acetone to determine all the characteristics of the propagation mode. The nonlinear coefficient of the fiber is determined by fitting the output spectra broadened by self-phase modulation with a new analytical expression giving the spectra of a hyperbolic secant pulse transmitted through a Kerr medium. The experiment allows a precise determination of the nonlinear index change n(2)(I) of acetone-d6 equal to (1.15 +/- 0.17) X 10(-19) m(2) W(-1). (C) 2010 Optical Society of America