Theory of adiabatic pressure-gradient soliton compression in hollow-core photonic bandgap fibers.

Adiabatic soliton compression by means of a pressure gradient in a hollow-core photonic bandgap fiber is investigated theoretically and numerically. It is shown that the duration of the compressed pulse is limited mainly by the interplay between third-order dispersion and the Raman-induced soliton frequency shift. Analytical expressions for this limit are derived and compared with results of detailed numerical simulations for a realistic fiber structure.