Pulse-amplitude-equalized output from a rational harmonic mode-locked fiber laser

Area of Science:

• Fiber laser technology
• Nonlinear optics
• Pulse shaping and control

Background:

• High-repetition-rate pulse generation is crucial for applications like optical communications and spectroscopy.
• Rational harmonic mode-locking (RHML) in fiber lasers offers a method to achieve high repetition rates.
• Achieving uniform pulse amplitude in RHML pulse trains remains a challenge.

Purpose of the Study:

• To demonstrate amplitude equalization of high-repetition-rate pulses from a rational harmonic mode-locked Er-doped fiber laser.
• To investigate the effectiveness of a nonlinear optical loop mirror (NOLM) for pulse amplitude control.
• To extend the capability of amplitude equalization to higher-order rational harmonic modes.

Main Methods:

• Utilizing an Er-doped fiber laser operating in the rational harmonic mode-locking regime.
• Employing a nonlinear optical loop mirror (NOLM) as the amplitude equalization mechanism.
• Characterizing the output pulse train using optical spectrum analyzers and autocorrelators.

Main Results:

• Successfully demonstrated amplitude equalization for the first time in this configuration.
• Achieved significant pulse amplitude equalization up to the ninth rational harmonic mode.
• The NOLM effectively suppressed amplitude variations in the RHML pulse train.

Conclusions:

• The proposed scheme effectively equalizes pulse amplitudes in high-repetition-rate fiber laser systems.
• This method offers a viable solution for generating uniform pulse trains for advanced applications.
• Further research can explore equalization at even higher harmonic orders and different laser systems.