Outreach

The researchers from the Institute of Cross-Disciplinary Physics and Complex Systems, IFISC (UIB-CSIC), Neus Oliver, Thomas Jüngling and Ingo Fischer have recently published their work in the prestigious journal of physics Physical Review Letters on the consistency properties of a chaotic laser: "Consistency properties of a chaotic semiconductor laser subject driven by optical feedback".

Most of us presume that when technical systems or even people react to the environment, they do it reliably, i.e. they respond in a similar way to similar stimuli or inputs. This concept is referred to as “Consistency” and has captured the attention of researchers due to the ubiquity of “drive-response” schemes in nature and technology. Remarkably, responses are not always consistent.

In this paper, consistency properties are investigated in an optical experiment: a semiconductor laser is driven by a chaotic optical signal twice. The laser is driven by a chaotic signal and a short time later, by an exact replica of this input signal. The two corresponding responses are then compared. This requires a high accuracy in the replay, which was achieved by storing the chaotic drive in an optical memory. Only by changing its operating conditions, the laser shows transitions from consistent to inconsistent responses. The authors develop a method to extract, directly from their experiment, the key quantity that determines the level of consistency and supports its understanding.

This work, carried out in the Nonlinear Photonics Laboratory of IFISC, might help to optimize various laser applications in communication and computation. Moreover, the developed methods inspire approaches to clarify how the neurons in our brain process information consistently.

Reference:

Neus Oliver, Thomas Jüngling, and Ingo Fischer, Physical Review Letters, 114, 123902 (2015). 
http://journals.aps.org/prl/abstract/10.1103/physrevlett.114.123902

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