High-power Yb-doped multicore ribbon fiber laser

A highly elongated double-clad ribbon fiber that comprises a pure-silica inner cladding with transverse dimensions of ?1.4?mm by 0.23?mm with a linear array of ten ytterbium-doped cores has been fabricated and operated in a simple laser configuration pumped by two diode stacks. The fiber laser yielded 320?W of output power at a center wavelength of 1045?nm in a combined beam with beam propagation factors of ?2 (perpendicular to the array) and ?150 (parallel to the array) for 576?W of launched pump power. The slope efficiency with respect to absorbed pump power was 62%. The prospects for further power scaling and improved beam quality and efficiency are discussed.