Time delay reservoir computing with short-external-cavity laser dynamics and phase encoding

Semiconductor lasers with optical feedback or optical injection have been studied in recent years, especially for their capabilities for complex signal generation and information processing. The nonlinear behavior of this system can be used for solving nonlinear computing tasks, when operating in a transient input transformation regime and exploiting memory induced by the feedback. For tasks that require memory, increasing the feedback rate is often beneficial. However, this might be accompanied by the onset of complex dynamics resulting in inconsistent input signal transformations, which are detrimental for computing. In this talk, I will discuss a semiconductor laser system that operates in a short-cavity regime, for which chaotic dynamics appear only under strong feedback conditions. The extended feedback operating regime avoiding chaos, compared to the long-cavity regime, allows to realize better memory properties. I will discuss the trade-off between memory, speed of computation, dimensionality, and consistency. I will show examples of various parameter conditions, identifying short external cavity regimes with strong optical feedback and injection, which offer high memory capacity avoiding the laser’s coherence collapse. I will also discuss how this system behaves when the input information is phase-encoded, and I will compare its performance to the commonly used amplitude encoding.

Zoom: https://uibuniversitat.zoom.us/j/87008849910