This paper outlines recent work at Corning Incorporated on fiber composition design and fabrication of a SBS-managed, large-mode-area (LMA), Yb-doped double-clad fiber for high-power, narrow-linewidth fiber laser applications. Through a detailed theoretical analysis for the SBS threshold in optical fibers, an Aluminum/Germanium (Al/Ge) counter-graded fiber-core composition profile has been proposed and demonstrated for reducing the SBS effect, via the reduced-overlap between optical and acoustic modes in the fiber design. Such Al/Ge counter-graded-composition-profile design overcomes the limitation in a multilayer fiber-core approach, in terms of the low-loss fiber fabrication. The new compositionally SBS-managed, LMA Yb-doped double-clad laser fiber fabricated through the new design, has shown more than ～7 dB improvement in SBS threshold over the conventional LMA fiber design. The new fiber offers exceptionally low passive-loss characteristics, and has been demonstrated with uncompromised high laser efficiency for high-power, narrow-linewidth fiber laser applications.
展开▼
