Mitigation of mode instability in laser oscillators based on deuterium loading

Area of Science:

• Fiber laser technology
• Laser physics
• Materials science

Background:

• Mode instability is a critical limitation in high-power fiber lasers.
• Ytterbium-doped fibers (YDFs) are widely used in high-power laser systems.
• Developing methods to suppress mode instability is crucial for laser power scaling.

Purpose of the Study:

• To investigate the effect of deuterium loading on mode instability in YDFs.
• To determine if deuterium loading can enhance the mode instability threshold.
• To assess the impact of deuterium loading on laser efficiency.

Main Methods:

• Loading Ytterbium-doped fiber (YDF) with deuterium for two and four weeks.
• Measuring the mode instability threshold power before and after deuterium loading.
• Evaluating laser efficiency at different power levels.

Main Results:

• Deuterium loading increased the mode instability threshold power by 16% (two weeks) and 35% (four weeks).
• The threshold power increased from approximately 459 W to 533 W and 622 W, respectively.
• Laser efficiencies remained largely unaffected, with values around 71.5% to 75.4%.

Conclusions:

• Deuterium loading is an effective strategy for mitigating mode instability in YDFs.
• This technique shows promise for the power scaling of high-power fiber lasers.
• Further research can explore optimal loading conditions and long-term stability.