201. Spectral beam combining of high-power fiber lasers
- Author
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Roy D. Mead, Angus Henderson, Ryan Stafford, Anping Liu, and Tracy W. Vatter
- Subjects
PHOSFOS ,Materials science ,business.industry ,Physics::Optics ,Polarization-maintaining optical fiber ,Long-period fiber grating ,Graded-index fiber ,Optics ,Double-clad fiber ,Fiber Bragg grating ,Fiber laser ,Physics::Accelerator Physics ,Optoelectronics ,Physics::Atomic Physics ,business ,Photonic-crystal fiber - Abstract
We have demonstrated spectral beam combining of two high power fiber lasers and obtained more than 40 W output power from the system. The system consists of two 30 W fiber lasers, a diffraction grating and a resonator. Both fiber lasers have broadband fiber Bragg gratings on the rear sides and share the diffraction grating and output coupler on the output sides. The wavelengths of the fiber lasers are determined by the optical dispersion provided by the grating and the collimating lens, as well as the fiber spacing. A model that analyzes dependence of laser line-width on beam quality of an SBC system is given in this paper. We also model a novel configuration that can significantly improve beam quality. The experimental results have shown that control of fiber laser line-width is the key to achieving high power SBC lasers. In addition, a new approach using three gratings is proposed and has been proven by the experiment. The new approach consists of three gratings, in which one grating is used by the SBC cavity to lock wavelengths while the other two combine the collimated beams without beam quality reduction. This approach has successfully improved beam quality M 2 from 11 to 2.0.
- Published
- 2004