Fig. 3.

Pulse broadening caused by the group velocity dispersion effect. a A schematic showing the pulse broadening due to the GVD effect when injecting an unchirped Gaussian pulse. b, c The frequency dependence of the temporal width in the output waveform measured at propagation distances x = 1 (red), 3 (green), and 5 (blue) mm by exciting Gaussian input pulses with T₀ = 1.2 and 0.7 μs, respectively. The solid line indicates the theoretical results estimated by substituting the experimentally obtained GVD coefficient k₂ in Fig. 2c into Eq. (8). Error bars denote one standard deviation