Alexandre Locquet

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We numerically study the synchronization of two unidirectionally coupled single-mode semiconductor lasers in a master-slave configuration. The master laser is an external-cavity laser that operates in a chaotic regime while for the slave laser we consider two configurations. In the first one, the slave laser is also an external-cavity laser, subjected to,(More)
We study numerically two distant unidirectionally coupled single-mode semiconductor lasers subject to coherent optical feedback. We show that two fundamentally different types of chaotic synchronization can occur depending on the strengths of the coupling and of the feedback of the receiver laser.
We investigate theoretically the possibility of retrieving the value of the time delay of a semiconductor laser with an external optical feedback from the analysis of its intensity time series. When the feedback rate is moderate and the injection current set such that the laser relaxation-oscillation period is close to the delay, then the time-delay(More)
We propose a secure communication scheme based on anticipating synchronization of two chaotic laser diodes, one subject to incoherent optical feedback and the other to incoherent optical injection. This scheme does not require fine tuning of the optical frequencies of both lasers as is the case for other schemes based on chaotic laser diodes subject to(More)
We show that the bifurcations between dynamical states originating in the nonlinear dynamics of an external-cavity semiconductor laser at constant current can be detected by its terminal voltage V. We experimentally vary the intensity fed back into the gain medium by the external cavity and show that the dc component V(dc) of V tracks the optical(More)
We study numerically the synchronization of external-cavity semiconductor lasers in a master-slave configuration, based on a Lang-Kobayashi-type model. Depending on the feedback and coupling strengths, the slave laser synchronizes with the injected optical field or with the injected field but lags in time. We show that these two types of synchronization(More)
We propose an efficient and fast bit-multiplexed encryption scheme exploiting hyperchaotic regimes of a single nonlinear oscillator with multiple time-delay feedback loops. Each data stream is encrypted by digitally modulating the values of the various time delays and decrypted using chaos synchronization and cross-correlation measurements. We have(More)
We analyze theoretically the polarization dynamics in unidirectionally coupled vertical-cavity surface-emitting lasers (VCSELs). The master VCSEL is subject to an isotropic optical feedback. The slave VCSEL is subject to an orthogonal optical injection from the master VCSEL, i.e., only the linearly polarized mode orthogonal to the dominant linearly(More)
This paper reports the experimental investigation of two different approaches to random bit generation based on the chaotic dynamics of a semiconductor laser with optical feedback. By computing high-order finite differences of the chaotic laser intensity time series, we obtain time series with symmetric statistical distributions that are more conducive to(More)
We analyze theoretically the effect of polarization mode competition on the synchronization of two unidirectionally coupled vertical-cavity surface-emitting lasers (VCSELs). Chaos in the master laser is induced by delayed optical feedback, and the slave laser is subject to isotropic optical injection from the master VCSEL. We show that the synchronization(More)