| 摘要 |
PURPOSE:To simplify constitution and to allow optical amplification with high efficiency by providing an excitation light source which is disposed apart from an optical fiber doped with a rare earth element and introduces excitation light of plural wavelengths to an optical fiber doped with the rare earth element. CONSTITUTION:The optical fiber 11 for amplification is interposed in the intermediate part of the optical fiber 10 for transmission. This optical fiber 11 for amplification is constituted of, for example, an Er-doped optical fiber. The excitation light source 13 is disposed apart a prescribed spacing from the optical fiber 11 for amplification on the lower side of the optical fiber 10 for transmission. Then, the total of the respective excitation powers of every wavelength of the plural wavelengths from the excitation light 13 is the substantial excitation power and, therefore, the desired excitation power is assured even if the excitation power at each wavelength is decreased. The substantial excitation light power is increased in the state of maintaining the excitation power of the small ratio to generate a nonlinear optical effect in this way and, therefore, the amplification rate thereof is improved. |
