Experimental synchronization of chaotic oscillations in mutually coupled semiconductor lasers

Synchronization of chaotic oscillations in two mutually coupled semiconductor lasers is experimentally investigated. Synchronized chaotic outputs from two mutually injected lasers are observed not only in low frequency fluctuation regimes of the order of MHz but also in high frequency fluctuation regions over the range of GHz. It is shown that the synchronization of our results is originated not from complete chaos synchronization but from injection phenomena in laser systems so called generalized chaos synchronization.