Raman gain saturation at high pump and Stokes powers

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Raman gain is crucial for optical amplification.
• Understanding saturation mechanisms is key for high-power fiber lasers and amplifiers.

Purpose of the Study:

• To investigate the Raman gain spectral profile in phosphosilicate fibers.
• To determine the saturation mechanisms at high optical powers.

Main Methods:

• Measurement of Raman gain spectral profiles.
• High-power pump and Stokes (signal) wave experiments.

Main Results:

• Homogeneous saturation of the Raman gain spectral profile was observed.
• Pump depletion was identified as the primary saturation mechanism.
• The Raman gain coefficient (gR) showed independence from pump and signal power up to approximately 3 W.

Conclusions:

• Phosphosilicate fibers exhibit predictable Raman gain saturation behavior.
• Pump depletion limits Raman gain in these fibers at high power levels.
• The findings are relevant for designing high-power fiber-based optical devices.