An excitable semiconductor micropillar laser with delayed optical feedback is able to regenerate pulses by the excitable response of the laser. It has been shown that almost any pulse sequence can, in principle, be excited and regenerated by this system over short periods of time. We provide experimental evidence that this is not true anymore in the long term: Rather, the system settles down to a stable periodic orbit with equalized timing between pulses. These observations are supported by the numerical analysis of a theoretical model of the system. Several such attracting periodic regimes with different numbers of equalized pulse timing may coexist and we study how they can be accessed with single external optical pulses of sufficient strength that need to be timed appropriately. Since the observed timing equalization and switching characteristics are generated by excitability in combination with delayed feedback, our results will be of relevance beyond the particular case of photonics, especially in neuroscience.

• Received 13 May 2019
• Revised 20 November 2019
• Accepted 24 January 2020

DOI:https://doi.org/10.1103/PhysRevResearch.2.023012

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society