Synchronization of Mutually Versus Unidirectionally Coupled Chaotic   Semiconductor Lasers
  Synchronization dynamics of mutually coupled chaotic semiconductor lasers are investigated experimentally and compared to identical synchronization of unidirectionally coupled lasers. Mutual coupling shows high quality synchronization in a broad range of self-feedback and coupling strengths. It is found to be tolerant to significant parameter mismatch which for unidirectional coupling would result in loss of synchronization. The advantages of mutual coupling are emphasized in light of its potential use in chaos communications. 
Noam Gross, Wolfgang Kinzel, Ido Kanter, Michael Rosenbluh and Lev   Khaykovich