Femtosecond pulse amplification system with GHz adjustable repetition rate based on harmonic mode locking

Guo Mengxue; Wang Kai; Huang Qianqian; Dai Lilong; Jiang Kailin; Zhang Bo; Li Weixi; Mou Chengbo

doi:10.11884/HPLPB202638.250347

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Article Navigation > High Power Laser and Particle Beams > 2026 > Accepted Manuscript

Guo Mengxue, Wang Kai, Huang Qianqian, et al. Femtosecond pulse amplification system with GHz adjustable repetition rate based on harmonic mode locking[J]. High Power Laser and Particle Beams. doi: 10.11884/HPLPB202638.250347

Citation:

Guo Mengxue, Wang Kai, Huang Qianqian, et al. Femtosecond pulse amplification system with GHz adjustable repetition rate based on harmonic mode locking[J]. High Power Laser and Particle Beams. doi: 10.11884/HPLPB202638.250347

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Femtosecond pulse amplification system with GHz adjustable repetition rate based on harmonic mode locking

doi: 10.11884/HPLPB202638.250347

Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, shanghai 200444, China

Received Date: 2025-10-15
Accepted Date: 2025-12-08
Rev Recd Date: 2025-12-25

Available Online: 2026-01-16

Abstract

Abstract

Background
Gigahertz-repetition-rate femtosecond fiber lasers have attracted increasing attention for applications requiring high temporal resolution and high average power, while most existing GHz fiber amplification systems are limited to fixed repetition rates.
Purpose
This work aims to realize repetition-rate-tunable amplification of gigahertz femtosecond pulses within a single fiber-based platform by employing a passively harmonic mode-locked fiber laser as the seed source.
Methods
The seed laser provides stable pulse operation with repetition rates tunable from 1 to 3 GHz. A two-stage fiber amplification scheme combined with dispersion management is implemented to maintain stable amplification over the entire tuning range. In the pre-amplification stage, controllable chirp is introduced to achieve near-linear temporal broadening, which effectively suppresses excessive nonlinear effects during power scaling. Pulse compression is subsequently implemented at the output using single-mode fiber.
Results
Experimental results show that stable pulse trains with regular temporal distribution are preserved throughout the tuning range. The maximum average output power reaches 2.1 W at a repetition rate of 3.1 GHz, while the shortest pulse duration of 195 fs is obtained at 2.0 GHz. After amplification, the side-mode suppression ratio remains higher than 33 dB.
Conclusions
These results indicate the feasibility of gigahertz repetition-rate-tunable amplification of femtosecond fiber lasers on a single all-fiber platform.
- ultrafast fiber laser,
- harmonic mode locking,
- adjustable repetition rate,
- pulse amplification,
- pulse compression

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References(23)

References

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