OPTICAL FIBER, LIGHT-EMITTING MODULE, AND OPTICAL FIBER AMPLIFIER

摘要

An optical fiber amplifier comprising an amplifying optical fiber (60) for amplifying a signal light by using inputted pumping light, a semiconductor light-emitting device (10) for outputting the pumping light, a focusing optical system (30) for focusing the pumping light, and light-guide optical fibers (20 to 22) for guiding light to the amplifying optical fiber through a core region, wherein the optical fibers (20 to 22) are so arranged that the direction in which the width of the core region at the light input face is maximum is the one in which the width of the inputted beam is maximum, and the maximum width D [ mu m] of the core region at the light input face satisfies the inequalities: L sin theta /NA