2  kW narrow-linewidth Yb-Raman fiber amplifier

Area of Science:

• Fiber laser technology
• Nonlinear optics
• Laser engineering

Background:

• Yb-Raman fiber amplifiers are crucial for high-power laser generation.
• Achieving high output power while maintaining narrow linewidth and stability is challenging.
• Second-order Raman scattering can limit amplifier performance.

Purpose of the Study:

• To report a high-power, narrow-linewidth Yb-Raman fiber amplifier.
• To demonstrate the effectiveness of temporally stable seed lasers for power scaling.
• To achieve over 2 kW output power at 1120 nm with high efficiency and stability.

Main Methods:

• Utilized two temporally stable seed lasers.
• Developed a Yb-Raman fiber amplifier configuration.
• Investigated performance at a pump power of 2.6 kW.

Main Results:

• Achieved over 2 kW output power at 1120 nm with 76.3% optical-to-optical efficiency.
• Maintained a narrow 3 dB linewidth between 0.41 nm and 0.53 nm.
• Suppressed second-order Raman Stokes light to -46.3 dB at 2 kW output.

Conclusions:

• Temporally stable seed lasers are superior for power scaling narrow-linewidth Yb-Raman fiber amplifiers.
• This work represents the first demonstration of an over 2 kW narrow-linewidth fiber laser at 1120 nm.
• The developed amplifier exhibits high power, narrow linewidth, and excellent intensity stability.