Abstract

It is well known that optical Kerr nonlinearity gives rise to interesting soliton phenomena either in the spatial or temporal domain. An interesting question is whether there exist solitons in both space and time domains simultaneously, and if yes, what are the characteristics of them. Such solitons look like light bullets with its energy localized in both space and time domains, and may be called spatio-temporal solitons. Light bullets in homogeneous Kerr media have also been studied before.¹ They are found unstable. The study reveals that the optical power large enough to make the beam self-guided is also large enough to cause wavefront instability. Recently we have investigated the propagation of spatio-temporal solitons through graded-index Kerr materials with variational methods.²,³ We found that stable spatio-temporal solitons exist if the path of propagation provides negative GVD and the pulse energy is less than a critical value. In the present paper we present numerical proof of the existence of such spatial-temporal solitons.

© 1995 IEEE