AMPLIFYING OPTICAL FIBER, AND OPTICAL FIBER AMPLIFIER AND OSCILLATOR USING SAME

摘要

Provided is an amplifying optical fiber capable of outputting light having favorable beam quality even when a higher-order mode is excited. Also provided is an optical fiber amplifier using the fiber. The amplifying optical fiber (50) comprises a core (51) and a cladding (52) for covering the core (51). The core (51) propagates light of a predetermined wavelength in an LP01 mode and/or an LP02 mode and/or an LP03 mode. An active element is added to at least a part of the region of the core (51) where the intensity of the LP01 mode is higher than the intensity of the LP02 mode and/or the LP03 mode when the LP01, LP02, and LP03 modes are normalized relative to power, and the addition is made at a higher concentration than in the center part of the core.