Enhanced extreme events in three cascade-coupled semiconductor lasers.

Area of Science:

• Nonlinear dynamics
• Semiconductor laser physics
• Chaos theory

Background:

• Extreme events (EEs) are rare, unpredictable phenomena observed in nature.
• Controlling or enhancing EEs has been a significant scientific challenge.
• Semiconductor laser systems can exhibit complex chaotic dynamics.

Purpose of the Study:

• To experimentally investigate the enhancement of extreme events (EEs) in a coupled semiconductor laser system.
• To explore the effect of cascade-injection on the characteristics of EEs.
• To understand the underlying mechanisms for EE enhancement in such systems.

Main Methods:

• Utilized a three cascade-coupled semiconductor laser system.
• Employed a continuous-wave optical injection to initiate chaotic dynamics.
• Sequentially injected laser outputs to create a cascade-injection structure.
• Performed experimental observations and numerical simulations.

Main Results:

• Demonstrated significant enhancement in the number and region size of extreme events (EEs).
• Observed that cascade-injection in a three-laser system further amplifies EEs compared to a two-laser system.
• Experimental results showed strong agreement with numerical simulations.
• Identified a wide injection parameter space for effective EE enhancement.

Conclusions:

• Cascade-injection in semiconductor laser systems provides a viable method for enhancing extreme events (EEs).
• The observed EE enhancement is robust across a wide parameter range.
• Noise plays a role in the evolution of regions with enhanced EEs, warranting further investigation.