Synchronization of power dropouts in coupled semiconductor lasers with external feedback - art. no. 013809

We present experimental evidence that the outputs in two unidirectionally c oupled semiconductor lasers with an external cavity, when operated in the r egime of low-frequency fluctuations, are synchronized in their dropout even ts but remain uncorrelated in the process of power recovery. We characteriz e such synchronized cyclic motions by measuring the difference of their Hil bert phases and entropy index. Our analysis of the coupled Lang-Kobayaski e quations in a master-slave configuration attributes the observed phenomenon to the different dynamical behavior of the slave laser in the buildup and plateau regions in phase space: the local unstable ol bits are robust again st coupling in the former but more susceptible to intervention in the latte r.