| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical fiber amplifier for long wavelength band, which amplifies a light signal having the long wavelength band (L band) of 1,570 nm to 1,610 nm. SOLUTION: When the pumping light of, for example, 980 nm which is outputted from a pumping laser diode is inputted to the optical amplification optical fiber; ASE in the opposite direction of a C band, namely, the band of about 1,530 nm to 1,560 nm wavelengths is generated. The light of the prescribed wavelength selected in opposite direction ASE or a 1,530 nm to 1,560 nm band range is reflected through a reflection means and is reinputted to the optical amplification optical fiber. A Bragg lattice filter and a reflection mirror can be used as reflection means. Light reflected by the reflection means is inputted again to the optical amplification optical fiber and is operated as pump light. Thus, the amplification gain of the long wavelength band against signal light is improved. |
