Raman amplification apparatus and distributed raman amplification system as well as starting up method for distributed raman amplification system

A distributed Raman amplification system, comprising:

• an optical transmission line;
• and
• first and second optical transmission apparatus connected to one end side and the other end side of said optical transmission line, respectively;
• said distributed Raman amplification system distributed Raman-amplifying light propagating along said optical transmission line;
• said first optical transmission apparatus including:
• a first optical monitoring signal source adapted to output an optical monitoring signal whose wavelength is set to the outside of a wavelength band of an optical main signal and which is to be transmitted to said second optical transmission apparatus along said optical transmission line;
• and
• a first optical monitor adapted to monitor power of the optical main signal transmitted from said first optical transmission apparatus and inputted to said optical transmission line and the optical monitoring signal outputted from said first optical monitoring signal source;
• said second optical transmission apparatus including a second optical monitor adapted to monitor power of the optical main signal and the optical monitoring signal, in the optical wavelength band, inputted to and received by said second optical transmission apparatus through said optical transmission line;
• one or both of said first and second optical transmission apparatus including a pumping light supplying section adapted to supply pumping light for the distributed Raman amplification to said optical transmission line;
• one of said first and second optical transmission apparatus including:
• a main signal wavelength light level acquisition section adapted to acquire information regarding transmission and reception levels of main signal wavelength light transmitted along said optical transmission line between said first and second optical transmission apparatus based on a result of the monitoring from said first and second optical monitors;
• a monitoring signal wavelength light level acquisition section adapted to acquire information regarding transmission and reception levels of the monitoring signal wavelength light having a wavelength different from that of the main signal wavelength light and transmitted along said optical transmission line between said first and section optical transmission apparatus based on monitoring results from said first and second optical monitors;
• a function information storage section adapted to store function information for deriving a noise amount and a gain by the Raman amplification regarding the monitoring signal wavelength light with respect to pumping light power supplied from said pumping light supplying section;
• and
• a transmission characteristic derivation section adapted to derive a transmission characteristic of said optical transmission line based on the information acquired by said main signal wavelength light level acquisition section and said monitoring signal wavelength light level acquisition section and the function information stored in said function information storage section.