Isamu Oshima, Katsuhiko Nishiyama, Katsuya Kurotori and Hirokazu Hayakawa
Recently, WDM systems have been increasingly installed. As a result, we have been developing optical fiber amplifiers for WDM systems.
Compact optical fiber amplifiers for single channel and small channel applications are needed for SDH systems and for WDM systems to compensate for insertion losses of optical passive components. In response, we have developed compact optical fiber amplifiers using a coaxial pumping laser. However higher output power and higher gain have recently been demanded. Therefore, compact optical fiber amplifiers using a butterfly pumping laser or a mini-DIL pumping laser have been developed. These amplifiers are reported in this paper.