Spectral broadening of femtosecond pulses in holey fibers

Summary form only given. Holey fibers are a new promising type of waveguides where electromagnetic waves are guided along a defect in a two-dimensional photonic band-gap structure consisting of a periodic array of air holes in a silica fiber. The missing hole in such a structure forms a defect in a two-dimensional photonic-crystal lattice, while the remaining part of the structure serves as a photonic crystal cladding, allowing robust low-loss single-mode waveguiding within a broad frequency range. Such fibers open a way to extend many ideas of the physics of photonic band-gap (PBG) structures to the optical range. At the same time, remarkable waveguiding properties of such fibers make it possible to form single waveguide modes with effective areas considerably exceeding those typical of conventional fibers. We investigate the spectral broadening of 150-fs pulses of a Ti:sapphire laser propagating through holey fibers with PBG-structure pitches varying from 1.4 to 32 /spl mu/m.