| 摘要 |
<p>First pumping light for Raman-amplifying signal light is inputted to the output end of the signal light, and second pumping light used for Raman-amplifying the first pumping light and having a wavelength shorter than that of the first pumping light is inputted to the input end of the signal light. The second pumping light is also inputted to the output end of the signal light. The first pumping light is also inputted to the input end of the signal light. The Raman amplification band of the second pumping light is made not to be overlapped with that of the signal light. The wavelength of the second pumping light is shorter than that of the first pumping light by the Raman shift of the amplifying optical fiber. The light source of either the first or second pumping light or both the light sources of them are multiplex light sources. The first pumping light is emitted from a semiconductor laser. Third pumping light for Raman-amplifying the second pumping light is directed to an optical transmission line. The signal light is transmitted through a transmission line using the Raman amplifying system.</p> |
