SRS suppression in multi-kW fiber lasers with a multiplexed CTFBG

Area of Science:

• Optics and Photonics
• Laser Physics
• Materials Science

Background:

• High-power fiber lasers are susceptible to nonlinear effects like stimulated Raman scattering (SRS).
• Effective SRS suppression is critical for maintaining beam quality and system efficiency in high-power laser applications.
• Existing methods for SRS suppression may face limitations at extremely high power levels.

Purpose of the Study:

• To experimentally investigate the performance of newly developed multiplexed chirped tilted fiber Bragg gratings (MCTFBGs) for SRS suppression.
• To evaluate the SRS suppression capability and thermal handling of MCTFBGs in a high-power fiber laser system.
• To demonstrate the potential of MCTFBGs as key components for high-power laser systems.

Main Methods:

• Fabrication of MCTFBG devices comprising five continuous segments of chirped tilted fiber Bragg gratings (CTFBGs).
• Inscribing CTFBGs into large-mode-area (LMA, 25/400μm) fibers.
• Testing the MCTFBG device in a master oscillator power amplification (MOPA) fiber laser system operating at >3 kW output power.

Main Results:

• Successful demonstration of SRS suppression using the MCTFBG device in a MOPA system.
• Achieved approximately 15 dB SRS suppression at >3 kW output power.
• Measured a high thermal handling capacity of approximately 1.48 °C/kW.

Conclusions:

• MCTFBGs exhibit excellent SRS suppression capabilities at very high power levels (>3 kW).
• The developed MCTFBG device demonstrates significant potential for high-power fiber laser systems.
• This work provides essential fiber grating components for effective SRS management in demanding laser applications.