title: High-power single-polarization and single-transverse-mode fiber laser with an all-fiber cavity and fiber-grating stabilized spectrum.
abstract: Conventionally, large-mode-area (LMA) fiber lasers use free-space polarizing components to achieve linear polarization output. External components, however, significantly limit laser robustness and power scalability. We demonstrate, to the best of our knowledge, the first high-power all-fiber cavity single-polarization single-transverse-mode LMA fiber laser, without the use of free-space polarizing components. This has been achieved by using tightly coiled high-birefringence 20 microm core LMA fiber. The lasing spectrum at 1085 nm has been stabilized by a fiber grating, spliced at one end of a LMA fiber. Up to 405 W of single-polarization output with a polarization extinction of >19 dB with a narrow spectrum (1.9 nm FWHM) and in a single-transverse mode (M2 < 1.1) has been demonstrated. The simplicity of a monolithic-cavity approach is highly beneficial for a number of applications, including the use of a fiber laser for nonlinear wavelength conversion and for coherent and spectral beam combining.
authors.affiliation: Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, Michigan 48109-2122, USA. liuch@umich.edu
authors.forename: Chi-Hung
authors.initials: CH
authors.lastname: Liu
authors.forename: Almantas
authors.initials: A
authors.lastname: Galvanauskas
authors.forename: Victor
authors.initials: V
authors.lastname: Khitrov
authors.forename: Bryce
authors.initials: B
authors.lastname: Samson
authors.forename: Upendra
authors.initials: U
authors.lastname: Manyam
authors.forename: Kanishka
authors.initials: K
authors.lastname: Tankala
authors.forename: David
authors.initials: D
authors.lastname: Machewirth
authors.forename: Stefan
authors.initials: S
authors.lastname: Heinemann