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Automation of Mode Locking in a Nonlinear Polarization Rotation Fiber Laser through Output Polarization Measurements
Published on: February 28, 2016
Femtosecond nonlinear polarization evolution based on cascade quadratic nonlinearities.
Optics Letters
|December 11, 2007
Summary
Researchers used nonlinear phase shifts from second-harmonic generation to control light polarization and intensity with ultrashort pulses. This enables passive amplitude modulation, showing promise for femtosecond laser mode locking.
Area of Science:
- Nonlinear Optics
- Ultrafast Laser Technology
Background:
- Second-harmonic generation (SHG) is a key nonlinear optical process.
- Controlling light polarization and intensity is crucial for laser applications.
- Femtosecond (fs) lasers require precise modulation techniques.
Purpose of the Study:
- To experimentally demonstrate intensity-dependent polarization evolution using nonlinear phase shifts.
- To develop a passive amplitude modulator based on nonlinear polarization rotation.
- To explore applications in femtosecond laser mode locking.
Main Methods:
- Utilizing type I phase-mismatched second-harmonic generation.
- Employing 100-fs pulses to induce nonlinear phase shifts.
- Implementing nonlinear polarization rotation for amplitude modulation.
Main Results:
- Achieved intensity-dependent polarization evolution.
- Demonstrated a passive amplitude modulator with up to ~50% modulation depth.
- Confirmed the effectiveness of nonlinear phase shifts in controlling light properties.
Conclusions:
- Nonlinear phase shifts in SHG offer a viable method for polarization and amplitude control.
- The developed amplitude modulator shows potential for advanced laser systems.
- This technique is promising for mode locking femtosecond bulk and fiber lasers.
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