RARE EARTH ELEMENT-DOPED MULTICORE FIBER, ITS PRODUCTION AND OPTICAL AMPLIFIER USING THAT OPTICAL FIBER

摘要

PURPOSE:To provide a rare earth element-doped multicore optical fiber which satisfies both of a high gain and a wide range and to provide an optical amplifier using this optical fiber. CONSTITUTION:This multicore optical fiber contains at least three optical fiber wires housed in a jacket 7. Each optical fiber wire consists of a core 5 having a high refractive index (nw) and outer diameter (Dw) with addition of at least one rare earth element and Al and a clad 6 which covers the core and has a low refractive index (nc) and thickness (t). In this structure, the value (1+2t/Dw) defined by the outer diameter (Dw) and thickness (t) ranges 1.1 to 2.5 and the amt. of Al added is at least 1wt.%.