Nonlinear dynamics of an injected quantum cascade laser

Area of Science:

• Optics and Photonics
• Semiconductor Lasers
• Nonlinear Dynamics

Background:

• Quantum cascade lasers (QCLs) are crucial semiconductor devices for mid-infrared applications.
• Understanding the stability of injected QCLs is vital for reliable device performance and novel applications.
• Previous studies have explored QCL stability, but analytical investigations into injected systems with varying parameters are ongoing.

Purpose of the Study:

• To analytically investigate the stability properties of an injected quantum cascade laser.
• To identify conditions leading to stable locking, pulsating intensities, and bistability.
• To map stability diagrams based on key operational parameters.

Main Methods:

• Analytical investigation using current estimates of laser parameters.
• Analysis of stability diagrams considering detuning, injection rate, and linewidth enhancement factor.
• Numerical verification using bifurcation diagrams derived from laser rate equations.

Main Results:

• Demonstrated that Hopf bifurcations can lead to pulsating laser intensities.
• Identified domains of coexistence between two stable steady states (bistability).
• Revealed coexistence between a stable steady state and stable periodic oscillations.

Conclusions:

• Injected quantum cascade lasers exhibit complex stability behaviors beyond simple locking.
• Pulsating intensities and bistability are significant potential operating regimes.
• The findings provide a comprehensive understanding of injected QCL dynamics for device design and application.