100 W all fiber picosecond MOPA laser

Area of Science:

• Optics and Photonics
• Laser Physics
• Fiber Laser Technology

Background:

• High-power picosecond fiber lasers are crucial for various applications.
• Direct amplification of low-repetition-rate seed lasers leads to detrimental nonlinear effects.
• Mitigating nonlinearities is essential for achieving high output power and good beam quality.

Purpose of the Study:

• To construct a high-power picosecond fiber laser in a master oscillator power amplifier (MOPA) configuration.
• To overcome nonlinear effects encountered during direct amplification of a picosecond seed laser.
• To achieve high average power and excellent beam quality in the amplified output.

Main Methods:

• Utilized an ytterbium-doped single mode fiber laser passively mode-locked by a semiconductor saturable absorber mirror (SESAM) as the seed source.
• Employed a self-made all-fiber device to octuple the seed laser's repetition rate from 59.8 MHz to approximately 478 MHz.
• Implemented a master oscillator power amplifier (MOPA) configuration for power amplification.

Main Results:

• The seed laser produced 20 mW average power with 13 ps pulse width and 59.8 MHz repetition rate.
• Increasing the repetition rate to 478 MHz effectively suppressed nonlinear effects during amplification.
• The final amplified laser achieved 96 W average power, 16 ps pulse width, M2 beam quality < 1.5, and 61.5% optical conversion efficiency.

Conclusions:

• Repetition rate multiplication is an effective strategy to mitigate nonlinear effects in high-power picosecond fiber MOPA systems.
• The developed all-fiber MOPA laser system demonstrates a viable approach for generating high-power picosecond pulses with high beam quality.
• This work contributes to the advancement of high-power fiber laser technology for demanding applications.