OPTICAL FIBER LASER, OPTICAL FIBER AMPLIFIER, AND MOPA-TYPE OPTICAL FIBER LASER

摘要

PPROBLEM TO BE SOLVED: To provide an optical fiber laser, an optical fiber amplifier, and an MOPA-type optical fiber laser wherein the generation of amplified return light (ASE) is prevented and their safety and lives are improved. PSOLUTION: This optical fiber laser comprises a rare earth added optical fiber which is at least a laser medium, a plurality of pumping light sources for optically pumping the rare earth added optical fiber, and an optocoupler for combining pumping light from respective pumping light sources and making the combined light incident into the rare earth added optical fiber. In this optical fiber laser wherein the pumping light is incident into the rare earth added optical fiber and laser oscillation takes place, the optocoupler is provided with a monitor port through which part of return light from the rare earth added optical fiber toward the pumping light source side propagates, and provided with a pumping light source control means for measuring return light intensity propagating through the monitor port, and preventing the amplification of the return light by reducing outputs of the pumping light sources when the light intensity exceeds a predetermined value. PCOPYRIGHT: (C)2007,JPO&INPIT