Semiconductor lasers under external perturbations can manifest a broad variety of complex dynamics in their output power, from periodicity to high dimensional chaos. One of their characteristic behaviors, when submitted to optical feedback, is their excitability. These optical excitable devices, that mimic neuronal behavior, can serve as building-blocks for novel, brain-inspired information processing systems. Neuronal systems represent and process the information of a weak external input through correlated electrical spikes. Semiconductor lasers with low to moderate optical feedback, i.e. in the low frequency fluctuations (LFF) regime, display optical spikes with intrinsic temporal correlations, similar to those of biological neurons. Here we study the laser optical spiking dynamics under the influence of direct pump current modulation, focusing on the influence of the modulation frequency and amplitude. We characterize time correlations in the sequence of optical spikes by using symbolic ordinal analysis. This powerful tool allows detecting symbolic patterns in the laser output, and to quantify the effect of the frequency and amplitude of the modulation on the patterns probabilities. The experimental results are in good qualitative agreement with simulations of the Lang and Kobayashi model.
We study the dynamics of semiconductor lasers with optical feedback and direct current modulation, operating in the regime of low frequency fluctuations (LFFs). In the LFF regime the laser intensity displays abrupt spikes: the intensity drops to zero and then gradually recovers. We focus on the inter-spike-intervals (ISIs) and use a method of symbolic time-series analysis, which is based on computing the probabilities of symbolic patterns. We show that the variation of the probabilities of the symbols with the modulation frequency and with the intrinsic spike rate of the laser allows to identify different regimes of noisy locking. Simulations of the Lang-Kobayashi model are in good qualitative agreement with experimental observations.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.