We have demonstrated nonlinear propagation in a 3-cell hollow core photonic crystal fiber. The reduced core size increases the nonlinear coefficient of the guided mode. However, the reduction in the expected soliton energy is small (a factor of approximately 2) as the dispersion of this fiber is also increased by the smaller core. We also demonstrate soliton compression using a 35 m 7-cell tapered fiber, compressing picosecond input pulses by over an order of magnitude.
Welch, M., Cook, K., Correa, R. A., Gerome, F., Wadsworth, W., Gorbach, A., Skryabin, D., & Knight, J. (2009). Solitons in hollow core photonic crystal fiber: Engineering nonlinearity and compressing pulses. Journal of Lightwave Technology, 27(11), 1644-1652. https://doi.org/10.1109/JLT.2009.2019731