Patent ID: 7894127

Claim:
An optical transmission system, comprising: one or more first light sources for Raman amplification that amplify signal light transmitting in an optical transmission line; and one or more second light sources for Raman amplification that are disposed at the positions adjoining said one or more first light sources for Raman amplification via said optical transmission line, wherein: each of said one or more first light sources for Raman amplification, comprising: a first pumping light source that emits first pumping light at a normal time as a pumping light source; and a first optical multiplexer that inputs said first pumping light to said optical transmission line, and each of said one or more second light sources for Raman amplification, comprising: a second pumping light source that emits second pumping light of the same wavelength band of said first pumping light at a normal time as a pumping light source; a spare pumping light source that emits spare pumping light of the same wavelength band of said first pumping light based on necessity, a number of said first light sources for Raman amplification and a number of said second light sources for Raman amplification being determined by a permissible failure rate of the optical transmission system; an optical coupler that couples said second pumping light and said spare pumping light; and a second optical multiplexer that inputs said coupled pumping light to said optical transmission line, wherein: in case that a failure occurred at said first or second pumping light source, said spare pumping light source is worked and said spare pumping light is emitted.