A survey is given on the theory of solitons in media defined by periodic nonlinear Klein-Gordon equations and in periodic media with Kerr nonlinearity. After a short introduction to soliton theory we consider various types of solitons, e.g. bright and dark, kink, gap and out-gap solitons and discuss future applications.
"Solitons in periodic structures", Proc. SPIE 1929, 17th International Conference on Infrared and Millimeter Waves, 19296J (14 December 1992); doi: 10.1117/12.2298352; https://doi.org/10.1117/12.2298352