Liu Chi-Hung, Galvanauskas Almantas, Khitrov Victor, Samson Bryce, Manyam Upendra, Tankala Kanishka, Machewirth David, Heinemann Stefan
Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, Michigan 48109-2122, USA.
Opt Lett. 2006 Jan 1;31(1):17-9. doi: 10.1364/ol.31.000017.
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.
