Self-focusing effects in periodic leaky-wave coupled (antiguided) and evanescent-wave coupled array structures are analyzed for what is to our knowledge the first time. The results obtained can be explained in terms of spatial gap solitons. For infinite-extent arrays of antiguides it is found that (for interelement-spacing values), below the in-phase-mode resonance, self-focusing occurs with increasing light intensity even when the medium is intrinsically self-defocusing (i.e., negative nonlinearity). If the medium has positive nonlinearity the analysis shows that antiguided arrays possess either self-focusing or self-defocusing properties depending on the parameters of the structure, whereas evanescent-wave in-phase coupled arrays always have self-focusing properties.
© 1993 Optical Society of America
Original Manuscript: April 26, 1993
Published: October 1, 1993
R. F. Nabiev, D. Botez, and P. Yeh, "Spatial gap solitons in periodic nonlinear structures," Opt. Lett. 18, 1612-1614 (1993)