Researchers at the Academy of Sciences and Czech Technical University (both in Prague, Czech Republic) have demonstrated a novel end-pumping scheme that can be used to develop more cost-effective high-power fiber amplifiers and lasers. Unlike other side- and end-pumping schemes that require a length of intermediate fiber or other bulk-coupling device to combine the pump and signal beam, the method connects the signal and pump fibers directly to the end face of a dual-clad (DC) fiber (with a tailored cross section) using a fusion splicer.
The method requires that the DC fiber shape matches the cross section of the two input fibers to facilitate splicing, and that the fiber cross section provides optimum absorption of the pump along the DC fiber. The fiber preforms that produce this desired cross section were fabricated by controlled polishing and fusing steps. High pump-coupling efficiency of the end-pumping scheme was experimentally demonstrated in a fiber-ring laser with an erbium- and ytterbium-doped DC fiber as the gain medium. Contact Pavel Peterka at [email protected].