Light Emission in the 1550 nm Band in Single-Mode Erbium-Ytterbium Co-Doped Optical Fiber by Solar Pumping

A single-mode erbium-doped optical fiber (SM-EDF) and a single-mode erbium-ytterbium co-doped optical fiber (SM-EYDF) were pumped using solar light. As a result, emitted light in the 1550 nm band was observed. Furthermore, we compared the emission properties of SM-EDF and SM-EYDF. The emission peak of SM-EYDF was more than twice as high as that of SM-EDF. The optimal fiber lengths for peak emission of SM-EYDF were found to be approximately 18.8 cm in the present experimental environment. This paper is the first to apply SM-EYDF to solar pumping and conduct detailed investigations, including fiber length characteristics. The possibility exists that increasing the power output and introducing oscillation systems can make them applicable to long-distance optical communication light sources and amplifiers driven solely by solar light.