| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that when plural stages of Raman amplifiers having the same gain-wavelength characteristic are used, a deviation of a Raman gain-wavelength characteristic becomes larger, and the flatness of the channel waveform of a wavelength multiplex transmission becomes worse, therefore, this needs to be compensated by an equalizer or the like. SOLUTION: The Raman amplifiers are used in combination so that a wavelength band of an upward projected curve including a gain maximum value of a first Raman amplifier and a wavelength band of a downward projected curve including a gain minimum value of a second Raman amplifier overlap each other, and a wavelength band of a downward projected curve including a gain minimum value of the first Raman amplifier and a wavelength band of an upward projected curve including a gain maximum value of the second Raman amplifier overlap each other. The same method is applied for three or more Raman amplifiers repeatedly. |
