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Single-mode operation of a coiled multimode fiber amplifier
Optics Letters
|December 8, 2007
Summary
Researchers developed a novel coiling technique for multimode fiber amplifiers. This method enhances beam quality, enabling higher power outputs for fiber lasers and amplifiers.
Area of Science:
- Optics and Photonics
- Fiber Lasers and Amplifiers
Background:
- Multimode fiber amplifiers typically suffer from poor beam quality due to multimode operation.
- Achieving high power output while maintaining excellent beam quality is a significant challenge in fiber laser development.
Purpose of the Study:
- To introduce a new method for achieving single-transverse-mode operation in multimode fiber amplifiers.
- To enable scaling of fiber lasers and amplifiers to higher pulse energies, peak powers, and average powers.
Main Methods:
- Coiling the gain fiber to induce bend loss, suppressing higher-order modes.
- Constructing a coiled amplifier using Ytterbium (Yb)-doped, double-clad fiber (core diameter 25 microm, numerical aperture ~0.1).
Main Results:
- Demonstrated single-transverse-mode operation with an M(2) value of 1.09 +/- 0.09 as an amplified spontaneous emission source.
- Achieved slope efficiency comparable to uncoiled amplifiers when seeded at 1064 nm.
Conclusions:
- The fiber coiling technique effectively achieves single-transverse-mode operation in multimode fiber amplifiers.
- This approach allows for significant power scaling of both pulsed and continuous-wave fiber sources without compromising beam quality.
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