Patent ID: 8941912
Filing Date: 2015-01-27
Classification: C03C,G02B,H01S

Abstract:
1. An ytterbium-doped optical fiber comprising: a core which consists of ytterbium, aluminum, phosphorus, fluorine, and at least one element selected from a group consisting of transition metal elements and rare earth elements other than ytterbium and erbium; and a cladding which encircles the core, wherein an aluminum oxide equivalent concentration of the aluminum in the core is 0.2 mol % or more; a diphosphorus pentaoxide equivalent concentration of the phosphorus is higher than the aluminum oxide equivalent concentration; and the core either does not contain germanium or contains less than 1.1 mol % of germanium in a germanium dioxide equivalent concentration, wherein the diphosphorous pentaoxide equivalent concentration in the core is greater than a summation of an ytterbium oxide equivalent concentration of the ytterbium and the aluminum oxide equivalent concentration in the core, and the ytterbium oxide equivalent concentration in the core is in a range of 0.01 to 1.0 mol %.