Contents
Source: MDPI
Soliton Mode-Locked Lasers and Kelly Sidebands
In soliton mode-locked lasers, a quasi-soliton pulse circulates in the laser resonator, experiencing effects of chromatic dispersion, nonlinearities, losses, and amplification. The periodic disturbances in the resonator can couple the soliton to a dispersive wave, leading to the formation of Kelly sidebands.
Understanding Kelly Sidebands
Kelly sidebands are narrow peaks superimposed on the soliton spectrum, providing information on the chromatic dispersion of the fiber. These sidebands are more common in soliton fiber lasers due to higher nonlinearity and dispersion compared to bulk lasers.
Factors Influencing Kelly Sidebands
The presence of Kelly sidebands indicates that the pulse duration is near its minimum value. The nonlinear phase shift per resonator round trip is inversely proportional to the pulse duration, so shorter pulses exhibit more pronounced sidebands.
Strategies for Mitigation
To reduce excessive Kelly sidebands, one can decrease the nonlinear phase shift per round trip by adjusting pulse duration or energy. Operating the laser with longer pulse durations or lower pulse energies can help mitigate issues with strong Kelly sidebands.
Conclusion
Understanding the formation and implications of Kelly sidebands in soliton mode-locked lasers is crucial for optimizing laser performance and stability. By managing factors such as pulse duration and energy, one can effectively suppress unwanted sidebands and enhance the laser’s overall efficiency.
Source: MDPI
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