Figure 3: Numerical simulation of pulse propagation in the waveguide and comparision with measurement.

(a) Calculated continuum spectra as a function of waveguide position at a coupled pulse energy of 330 pJ. The pulse is launched in the TM mode of the waveguide with mode area 0.76 μm². The colour bar (inset) applies to (a,c–e). (b) Top-view photographs of scattered light from the surface of the waveguide. The photographs were taken at pulse energies ranging from 330 to 1,100 pJ (left to right side). As indicated by the dashed line, the pulse travels in the waveguide from the bottom to the top of the image. Dispersive wave generation occurs in the ultraviolet and is therefore not visible in the image. The grey line superimposed on the photographs is the length at which dispersive wave generation occurs as predicted by the simulation. The spectral breathing of the input pulse results in a periodically visible orange-red emission that correlates with the calculation. (c) Calculated continuum spectra as a function of waveguide position at a pulse energy of 1,100 pJ. (d,e) Calculated spectrograms of the optical pulse propagating in the waveguide corresponding to (c). The spectrogram in d is at waveguide position 0.16 cm where dispersive wave is generated. The spectrogram in e is at the waveguide output.