Raman rogue waves in a partially mode-locked fiber laser

Area of Science:

• Nonlinear Optics
• Fiber Laser Physics
• Spectral Dynamics

Background:

• Intracavity Raman conversion is a key phenomenon in fiber lasers, influencing spectral characteristics.
• Understanding spectral fluctuations is crucial for laser stability and performance.
• Raman scattering can lead to complex pulse dynamics, including noise-like pulses and rogue waves.

Purpose of the Study:

• To experimentally investigate spectral fluctuations induced by intracavity Raman conversion.
• To analyze the statistical properties of Raman emission under different cavity gain conditions.
• To identify the origins of intracavity rogue waves in a passively mode-locked fiber laser.

Main Methods:

• Utilized a passively partially mode-locked, all-normal dispersion fiber laser.
• Employed dispersive Fourier transformation (DFT) for single-shot spectral measurements.
• Analyzed spectral fluctuations and probability distributions of Raman-induced noise-like pulses.

Main Results:

• Observed sporadic Raman emission with rogue-wave-like probability distributions at low cavity gain.
• Demonstrated a transition to a saturated regime with Gaussian statistics at high pump powers.
• Revealed intracavity rogue waves originating from cascaded Raman dynamics.

Conclusions:

• The spectral behavior of Raman-induced noise-like pulses is highly dependent on cavity gain.
• Rogue-wave statistics characterize Raman emission in low-gain regimes, transitioning to Gaussian in high-gain regimes.
• Cascaded Raman processes are a significant source of intracavity rogue waves in this laser system.