| 摘要 |
The present invention relates to a Raman amplifier which is hard to deteriorate signal waveforms, so that it realizes an excellent transmission quality. In this Raman amplifier, an optical waveguide for Raman-amplifying signal light when pumping light is supplied thereto has a zero-dispersion wavelength lambd0 shifted from a center wavelength lambdcenter (=(lambdS, rms+lambdP, rms)/2) existing between a center-of-gravity wavelength lambdS, rms of the signal light, which is a mean weighted with respective powers of wavelength components included in the signal light, and a center-of-gravity wavelength lambdP, rms of the pumping light, which is a mean weighted with respective powers of wavelength components included in the pumping light, by such a wavelength spacing that non-degenerate type four-wave mixing is effectively suppressed. In particular, when the Raman amplification optical waveguide has a positive dispersion slope with respect to the signal light, the zero-dispersion wavelength lambd0 of the Raman amplification optical waveguide is shorter than the center wavelength lambdcenter. When the Raman amplification optical waveguide has a negative dispersion slope with respect to the signal light, the zero-dispersion wavelength lambd0 of the Raman amplification optical waveguide is longer than the center wavelength lambdcenter.
|
