IEEE Study Reveal the Physics of Laser Emission from Mamyshev Oscillator

Researchers demonstrate how harmonic mode-locking builds up in fiber-based Mamyshev oscillators, unraveling the dynamics of laser emission

PISCATAWAY, N.J., June 26, 2025 /PRNewswire/ -- Harmonic mode-locking (HML) is an advanced form of mode-locking process where multiple laser pulses are produced within one round trip of light. Mamyshev oscillators (MOs) employing HML are used for several advanced applications such as optical communication, frequency metrology, and micromachining.

Despite increasing applications of HML MOs, understanding the light buildup dynamics of HML within these lasers is experimentally challenging. In a recent study published in Journal of Lightwave Technology, researchers from Hunan University, China have uncovered the buildup dynamics of HML in an all-fiberized erbium-doped MO. They successfully obtained HML pulse outputs of different orders. The signal-to-noise ratio of all harmonic pulse trains from the all-fiber MO exceeded 80 dB, demonstrating the high stability of the output.

They identified five distinct ultrafast phases (relaxation oscillation, multi-pulses operation, pulse collapse reconstruction, unstable HML, and a stable HML state) that occur between the injection of seed pulses into the laser cavity and the stable emission of HML pulses from the MO. Notably, the identified process of stable HML generation was different from the conventional pulse splitting effect thought to result in laser emission dynamics in MOs. The experimental findings were further supported using numerical simulations.

Using the TS-DFT technique, they found that the generation of HML in the MO was not dominated by the conventional single pulse splitting effect but rather by the amplification of multiple seeding pulses within the oscillator.

"Our results showed that the initial seed pulses within the cavity evolve into stable independent pulses through processes such as gain amplification and energy redistribution, eventually leading to a stable HML state within the resonator", observes Dr. Li.

Overall, this study has extended our understanding of light buildup dynamics in MOs. The insights offered by the study may lead to improved designs of MOs – advancing their use across several fields.

Reference
Title of original paper: Resolving the Buildup Dynamics of Harmonically Mode-Locked Mamyshev Oscillator

Journal: Journal of Lightwave Technology
DOI: 10.1109/JLT.2025.3570159

Contact:
Kristen Amoroso
+1(732) 562-6694
[email protected]

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SOURCE IEEE Photonics Society