Identical chaotic synchronization and bidirectional message transmission in incoherently coupled semiconductor laser diodes

TL;DR

This paper investigates chaos-based bidirectional communication using incoherently coupled semiconductor lasers, demonstrating synchronization and message transmission, but with limitations due to relaxation oscillations affecting bit rate.

Contribution

It extends chaos synchronization and message transmission techniques to incoherent coupling in semiconductor lasers, highlighting differences from coherent coupling.

Findings

Synchronization is possible in incoherent coupling similar to coherent cases.

Chaotic regime exhibits relaxation oscillations with chaotic envelopes.

Bit rate is limited by relaxation oscillation frequency.

Abstract

A chaos-based communication scheme allowing simultaneous bidirectional message transmission (Opt. Lett. 32, 403, 2007) is investigated numerically. Incoherent feedback and coupling case is analyzed, which is expected in real long-distance optical communication systems. It is shown that identical synchronization of chaotic laser waveforms and bidirectional message transmission are possible as in the coherent coupling case. However, the chaotic regime at incoherent feedback and coupling is quite different. It is regular destabilized relaxation oscillations with the chaotic envelope. Such dynamics leads to restriction of the transmitting signal bit rate by a portion of relaxation oscillations frequency.