| 摘要 |
PURPOSE:To eliminate the need of conversion between an optical signal and an electric signal to reduce energy losses by using an optical fiber, where a rare-earth element is doped, as an amplifying element which directly amplifies the optical signal. CONSTITUTION:The output terminal of a coupler 3 is connected to the leading edge of an optical fiber 5 as the amplifying element through an optical fiber 4, and the input terminal of a filter 6 which permits only the light having a prescribed wavelength to pass through is connected to the treailing end of the optical fiber 5. In this optical fiber 5, not only neodymium (Nd) as a prescribed rare-earth element but also ytterbium (Yb) and aluminum (Al) as other elements are doped mainly in the part of a core 11. Since Nd, Yb, and Al are doped in the optical fiber 5, the optical signal having a waveform corresponding to an input optical signal is amplified and outputted by induced emission. The conversion between the optical signal and the electric signal is unnecessary to reduce the energy losses. |
