In physics, a pulse is a generic term describing a single disturbance that moves through a transmission medium.
This medium may be vacuum (in the case of electromagnetic radiation) or matter, and may be indefinitely large or finite.
A pulse will reflect off a fixed end and return with the opposite direction of displacement.
Scalar dark solitons (linearly polarized dark solitons) can be formed in all normal dispersion fiber lasers mode-locked by the nonlinear polarization rotation method and can be rather stable.
Vector dark solitons[2][3] are much less stable due to the cross-interaction between the two polarization components.
Figure 1: A pulse reaching the end of the medium, the end point is free. The successive positions of the pulse is drawn black, red, green, blue, black, red, green. The final green curve is the initial curve of figure 2.
Figure 2: The reflection of the pulse. The successive positions of the pulse is drawn green, blue, black, red, green, blue. The initial green curve is the final curve of figure 1
Figure 3: A pulse reaching the end of the medium, the end point is fixed. The successive positions of the pulse is drawn black, red, green, blue, black, red, green. The final green curve is the initial curve of figure 4.
Figure 4: The reflection of the pulse. The successive positions of the pulse is drawn green, blue, black, red, green, blue. The initial green curve is the final curve of figure 3
Figure 5: Animation corresponding to figures 3 and 4.
