Addressing modulational instability in anti-resonant hollow-core fibers for pulse compression

Area of Science:

• Nonlinear optics
• Fiber optics
• Ultrafast science

Background:

• Modulational instability (MI) in gas-filled anti-resonant hollow-core fibers (AR-HCFs) leads to pulse break-up and coherence loss.
• MI is a parasitic effect in pulse broadening and compression, causing shot-to-shot fluctuations in peak power.

Purpose of the Study:

• To compare two AR-HCFs designed to either enhance or suppress MI.
• To investigate the impact of anti-resonant element (ARE) wall thickness on MI gain.
• To determine methods for increasing the pulse energy limit for stable ultrafast pulse compression.

Main Methods:

• Experimental studies of pulse propagation in AR-HCFs.
• Numerical simulations to support experimental findings.
• Comparison of AR-HCFs with varying ARE wall thicknesses.

Main Results:

• MI gain can be significantly reduced by optimizing ARE wall thickness.
• Suppression of MI allows for higher input pulse energies.
• Stable ultrafast pulse compression is achieved at increased energy levels.

Conclusions:

• Judicious selection of ARE wall thickness is crucial for controlling MI in AR-HCFs.
• Optimized AR-HCFs enable higher energy scaling for ultrafast pulse compression.
• This work provides a pathway to overcome limitations in high-power ultrafast fiber lasers.