Light Bullet Modes in Self-Induced-Transparency Media with Refractive   Index Modulation
  We predict the existence of a new type of spatiotemporal solitons ("light bullets") in two-dimensional self-induced-transparency media with refractive index modulation in the direction transverse to that of pulse propagation. These self-localized guided modes are found in an approximate analytical form, their existence and stability being confirmed by numerical simulations, and may have advantageous properties for signal transmission. 
M. Blaauboer, G. Kurizki, B.A. Malomed