Highly coherent visible dispersive wave radiation in suspended core fibers

Abstract

Visible dispersive wave (DW) generation is used in several applications, such as in dispersion measurements, fluorescence microscopy, and biomedicine. The effects of fiber characteristics, pump pulse width, and average pump power on DW generation are investigated in suspended core fiber (SCF) by numerical simulation. The coherence of visible DW is high in all cases. The dynamics behind DW generation are analyzed based on pulse evolution spectrograms. Energy exchange between DW and soliton occurs mainly in the first contraction of the first emitted soliton. Numerical simulations using experimental parameters indicate that the DW can be compressed down to approximately 40 fs. In experiments, under the pump pulse with a pulse width of 50 fs and pump wavelength of 1 μm, an isolated DW is generated at ∼480 nm in SCF1 featuring a large fiber core. Under the same pump conditions, isolated DWs at ∼466 nm and ∼485 nm with full width at half maximum of ∼40 nm and conversion efficiency of ∼10% are achieved in SCF2 with a small fiber core. The coherence of DW is better than that of the infrared component based on the comparisons of the pulse trains of DW and the infrared component in supercontinuum. The influence of OH− content on DW generation is also experimentally analyzed.