Raman amplifier and optical communication system including the same

Abstract

The present invention relates to a Raman amplifier where flexibility in device design considering both of Raman amplification and dispersion compensation is high. In the Raman amplifier, the Raman amplification optical fiber included in the optical amplification section and the dispersion compensating optical fiber included in the dispersion compensation section are arranged while being optically connected to each other. Since the optical amplification section and the dispersion compensation section are provided as independent optical devices, one device can be designed without being restricted to the design conditions of the other device.

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         53 . A Raman amplifier provided at a predetermined position of an optical fiber transmission line and having an input end for entering signal light which propagates through said optical fiber transmission line and an output end for outputting said Raman-amplified signal light, comprising: 
 an optical amplification section provided between said input end and said output end, and including a Raman amplification optical fiber for Raman-amplifying signal light which enters through said input end by supplying pumping light into said Raman amplification optical fiber;    wherein said Raman amplifier further comprises a dispersion compensation section provided between said input end and said output end while being optically connected to said Raman amplification optical fiber, said dispersion compensation section compensating for a total chromatic dispersion of said optical fiber transmission line positioned outside of said Raman amplifier and said Raman amplification optical fiber positioned inside of said Raman amplifier, in a signal light wavelength band, and    wherein said Raman amplification optical fiber has an effective area of 30 μm 2  or less in the pumping light wavelength, and a parameter g R  of 2.3×10 −14  m/W or more.    
     
     
         54 . A Raman amplifier provided at a predetermined position on an optical fiber transmission line and has an input end for entering signal light which propagates through said optical fiber transmission line and an output end for outputting said Raman-amplified signal light, comprising: 
 an optical amplification section which is installed between said input end and said output end, and includes a Raman amplification optical fiber for Raman-amplifying signal light which enters through said input end by the supply of pumping light into said Raman amplification optical fiber;    a dispersion compensation section provided between said input end and said output end while being optically connected to said Raman amplification optical fiber, and compensates for a total chromatic dispersion in the signal light wavelength of said optical fiber transmission line positioned outside of said Raman amplifier and said Raman amplification optical fiber positioned inside of said Raman amplifier; and    a pumping light source supply system, comprising a first pumping light source, and supplies said pumping light to said Raman amplification optical fiber, and a first optical multiplexing structure for guiding the pumping light from said first pumping light source to said Raman amplification optical fiber without passing through said dispersion compensating optical fiber, and    wherein said Raman amplification optical fiber has an effective area of 30 μm 2  or less in the pumping light wavelength, and a parameter g R  of 2.3×10 −14  m/W or more.