High-frequency chaotic dynamics enabled by optical phase-conjugation.

Émeric Mercier,Delphine Wolfersberger,Marc Sciamanna

doi:10.1038/srep18988

Émeric Mercier, Delphine Wolfersberger + Show 1 more

Open Access

https://doi.org/10.1038/srep18988

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Journal: Scientific Reports	Publication Date: Jan 7, 2016
Citations: 21	License type: CC BY 4.0

Affiliation: University of Paris-Saclay

Abstract

Wideband chaos is of interest for applications such as random number generation or encrypted communications, which typically use optical feedback in a semiconductor laser. Here, we show that replacing conventional optical feedback with phase-conjugate feedback improves the chaos bandwidth. In the range of achievable phase-conjugate mirror reflectivities, the bandwidth increase reaches 27% when compared with feedback from a conventional mirror. Experimental measurements of the time-resolved frequency dynamics on nanosecond time-scales show that the bandwidth enhancement is related to the onset of self-pulsing solutions at harmonics of the external-cavity frequency. In the observed regime, the system follows a chaotic itinerancy among these destabilized high-frequency external-cavity modes. The recorded features are unique to phase-conjugate feedback and distinguish it from the long-standing problem of time-delayed feedback dynamics.

Highlights

Wideband chaos is of interest for applications such as random number generation or encrypted communications, which typically use optical feedback in a semiconductor laser
We will show that the bandwidth enhancement can be attributed to the onset of destabilized self-pulsing modes[15], called external-cavity modes (ECMs), which go up in frequency as we increase the reflectivity of our phase-conjugate mirror[16,17,18]
We have investigated chaotic behavior (LFF regime) of a semiconductor laser subjected to phase-conjugate feedback (PCF) and conventional optical feedback (COF) in a long cavity with moderate to strong feedback strength

Summary

Introduction

Wideband chaos is of interest for applications such as random number generation or encrypted communications, which typically use optical feedback in a semiconductor laser. We will show that the bandwidth enhancement can be attributed to the onset of destabilized self-pulsing modes[15], called external-cavity modes (ECMs), which go up in frequency as we increase the reflectivity of our phase-conjugate mirror[16,17,18].

Results

Conclusion