Absence of Galilean invariance for pure-quartic solitons

Optical temporal solitons, arising from self-phase modulation and negative quadratic (beta(2)) dispersion, are Galilean invariant, and therefore their properties do not depend on their group velocity. This is no longer true for pure-quartic soliton pulses arising from quartic( )(beta(4)) dispersion, for which a change in group velocity necessarily leads to nonzero quadratic and cubic (beta(3)) dispersion. Analyzing the generalized nonlinear Schrodinger equation for such dispersion relations analytically and numerically, we find that pure-quartic solitons are members of a larger family traveling at other speeds. These solitons, which appear to be stable, have a complex phase structure and have an asymmetric spectrum. Our results extend the understanding of solitons arising from high orders of dispersion.

Automated summary

In this study, optical properties of pure-quartic solitons are examined. They are found to be stable solitons with complex phase structure and asymmetric spectrum, traveling at different speeds as members of a larger family arising from high orders of dispersion.