| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To prevent both of a signal light output level and wavelength characteristics from being deteriorated at the final stage even when a failure occurs in a pumping light source in light sources for Raman amplification, to make the number of components in the system not large and to suppress the cost of the system as a whole. <P>SOLUTION: The optical transmission system is constructed by providing spare pumping light sources 11, 12 for redundant use to a light source 1<SB>n</SB>for Raman amplification used after n times of relaying while no spare pumping light source for redundant use is provided to light sources 1<SB>1</SB>to 1<SB>n-1</SB>for Raman amplification. When any pumping light source out of the light sources 1<SB>1</SB>to 1<SB>n-1</SB>or the light source 1<SB>n</SB>for Raman amplification becomes defective, the spare pumping light is outputted by making the spare pumping light sources 11, 12 operate so as to recover the signal light output level and the wavelength characteristics to a state before the failure of the pumping light source has occurred. <P>COPYRIGHT: (C)2004,JPO</p> |
