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Tunable switching between stable and periodic states in a semiconductor laser with feedback
Optics Letters
|November 1, 2017
Summary
Optical feedback in semiconductor lasers induces switching between stable and periodic states. This tunable switching, observed numerically and experimentally, generates square-wave modulated microwave signals.
Area of Science:
- Nonlinear Dynamics
- Semiconductor Laser Physics
- Photonics
Background:
- Semiconductor lasers exhibit complex dynamics under external influences.
- Optical feedback can lead to phenomena like chaos and mode hopping.
- Understanding nonlinear states is crucial for laser applications.
Purpose of the Study:
- Investigate feedback-induced switching between nonlinear dynamical states in a semiconductor laser.
- Explore the characteristics and tunability of this switching behavior.
- Assess the potential for photonic microwave generation.
Main Methods:
- Numerical simulations to unveil state switching.
- Experimental setup with a single-mode, long-cavity semiconductor laser.
- Optical feedback applied and intensity time series analyzed.
Main Results:
- Observed switching between stable (continuous-wave) and periodic (relaxation oscillation) states.
- Switching occurs with a period equal to the laser's round-trip time (τ).
- Tunable duty cycle of the periodic state achieved by adjusting feedback strength.
Conclusions:
- Demonstrated feedback-induced, tunable state switching in semiconductor lasers.
- Confirmed experimental observation of a square-wave envelope modulated on a microwave carrier.
- Identified potential application in square-wave modulated photonic microwave generation.
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