Related Experiment Video
Updated: May 15, 2025
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Low-cost Custom Fabrication and Mode-locked Operation of an All-normal-dispersion Femtosecond Fiber Laser for Multiphoton Microscopy
Published on: November 22, 2019
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Transverse mode coupling in monolithic few-mode fiber laser oscillators
Binyu Rao1,2, Jinbao Chen3,4, Zefeng Wang5,6
1College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, China.
Light, Science & Applications
|May 11, 2025
Summary
This study investigates transverse mode instability (TMI) in few-mode fiber lasers. By managing modal power distribution with optimized low-reflection gratings, a record 10.07 kW output was achieved without TMI.
Area of Science:
- Physics
- Optics
- Materials Science
Background:
- Transverse mode instability (TMI) is a key limitation in high-power fiber laser scaling.
- Nonlinear thermal-optical coupling and mode competition complicate TMI in fiber oscillators.
Purpose of the Study:
- To explore TMI phenomena in few-mode fiber oscillators using a holistic approach.
- To develop strategies for mitigating TMI and achieving higher power outputs.
Main Methods:
- Solving steady-state thermal-optic coupling equations for simulations.
- Investigating the correlation between bending loss and TMI threshold.
- Designing low-reflection gratings (LRs) to manage modal power.
- Optimizing fiber coiling and LR linewidth.
Main Results:
- Discovered a non-monotonic correlation between bending loss and TMI threshold, contradicting two-mode interaction theory.
- Demonstrated that modal power redistribution in independent frequency domains mitigates TMI.
- Achieved a record 10.07 kW monolithic fiber laser output without observable TMI.
Conclusions:
- Modal power redistribution via LR linewidth design is a novel approach to mitigate TMI.
- Optimized LR linewidth and fiber coiling significantly elevate the TMI threshold.
- Findings offer new insights into mode decoupling for high-power fiber lasers and fiber communications.
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