Modeling Er/Yb fiber lasers at high powers.

Area of Science:

• Photonics
• Materials Science
• Laser Physics

Background:

• Conventional models for Er/Yb co-doped fibers assume uniform ytterbium ion involvement in energy transfer.
• These models predict output power clamping due to ytterbium parasitic lasing, which contradicts experimental observations of continued, albeit slower, power growth.
• Previous explanations involving elevated temperatures or mode-dependent effects were found to be insignificant.

Purpose of the Study:

• To develop a novel model for Er/Yb co-doped fibers that accurately explains experimental observations.
• To investigate the role of isolated ytterbium ions in energy transfer dynamics.
• To challenge the assumptions of conventional models regarding ion homogeneity.

Main Methods:

• Development of a new theoretical model incorporating isolated ytterbium ions.
• Analysis of energy transfer mechanisms in Er/Yb co-doped fiber systems.
• Comparison of model predictions with experimental data, including output power behavior and parasitic lasing phenomena.

Main Results:

• The new model, accounting for isolated ytterbium ions, successfully explains the observed output power growth beyond the onset of ytterbium parasitic lasing.
• Elevated temperature and mode-dependent effects were determined to play minor roles in the observed phenomena.
• The model provides a more accurate representation of the complex energy transfer dynamics in these fiber systems.

Conclusions:

• The existence of isolated ytterbium ions is crucial for understanding the performance of Er/Yb co-doped fibers at high power levels.
• Conventional models assuming uniform ion distribution are insufficient to explain experimental results.
• The developed model offers a more robust framework for designing and optimizing Er/Yb co-doped fiber lasers and amplifiers.