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Low-frequency self-pulsations in asymmetric external-cavity semiconductor lasers due to multiple-feedback effects
Optics Letters
|September 16, 2009
Summary
External-cavity semiconductor lasers with tilt asymmetries exhibit low-frequency self-pulsations. A new rate-equation model explains these pulsations, crucial for understanding laser instabilities and chaos.
Area of Science:
- Optics and Photonics
- Semiconductor Physics
- Nonlinear Dynamics
Background:
- External-cavity semiconductor lasers (ECSLs) are vital components in various applications.
- Understanding dynamical instabilities in ECSLs is crucial for reliable operation.
- Deliberate introduction of asymmetries can influence laser dynamics.
Purpose of the Study:
- To investigate the dynamical stability of ECSLs with intentional tilt asymmetries.
- To explain the origin of experimentally observed low-frequency self-pulsations.
- To elucidate the dependence of self-pulsation characteristics on various physical parameters.
Main Methods:
- Development of a novel rate-equation model incorporating a time-dependent effective reflectivity.
- Application of small-signal analysis to the developed rate-equation model.
- Experimental observation and characterization of self-pulsations in tilted ECSLs.
Main Results:
- The new model successfully explains low-frequency self-pulsations in tilted ECSLs.
- Self-pulsation frequency is dependent on feedback asymmetry, injection current, and cavity length.
- The strength and degree of feedback asymmetry significantly influence self-pulsation behavior.
Conclusions:
- Tilt asymmetries in ECSLs can lead to predictable low-frequency self-pulsations.
- The developed rate-equation model provides a robust framework for analyzing ECSL dynamics.
- These findings are essential for controlling and interpreting complex dynamical behaviors in ECSLs, including chaos.
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