OPTICAL FIBER FOR AMPLIFICATION

摘要

PURPOSE:To highly the gain of signal light with small power of exciting light by doping the center core of an optical fiber a rare earth element. CONSTITUTION:The center core 3a of a convex optical fiber B is doped with a rare earth element. When the relation between the power distribution p(r) of amplified signal light and the refractive index distribution n(r) of the fiber B is examined, the region p<+> of the distribution p (r) above a standard level pO extends to the entire cross-sectional area of the core 3a. The entire cross-sectional area of the core 3a contributes to the amplification of signal light and sufficiently high gain is enabled.