Isochronous Synchronization Between Chaotic Semiconductor Lasers Over 40-km Fiber Links

A long-distance isochronous chaos synchronization system, composed of a driving chaotic semiconductor laser and twin semiconductor lasers, is demonstrated experimentally. Via a driven chaotic signal which is generated by the driving chaotic semiconductor laser subject to external feedback and then injects into the twin semiconductor lasers by a pair of 20-km single-mode fibers, respectively, isochronous synchronization between the twin semiconductor lasers is experimentally observed. Further results show that high-quality isochronous synchronization can still be maintained even though the correlation coefficient between the driving laser and twin lasers is low. In addition, the bandwidth of synchronized chaotic signals is enhanced to more than 10 GHz although the bandwidth of driving signal is about 5.7 GHz.