Patent ID: 7177073
Filing Date: 2007-02-13
Classification: H01S,H04B

Abstract:
1. A Raman amplifier comprising: a second order Raman pump source configured to generate a second order Raman pump light amplifying a signal beam propagating along a first optical fiber length by second order Raman amplification; a first order Raman pump source configured to generate first order Raman pump light which amplifies said signal beam propagating along a second optical fiber length by first order Raman amplification; and a four-port optical coupler which is connected to said second-order Raman pump source and said first-order Raman pump source, said four-port optical coupler being configured to mix a smaller signal fraction of said first order pump signal and a larger fraction of said second order pump signal to generate a first output pump signal which is inserted into said first fiber length and to mix a larger signal fraction of said first order pump signal and a smaller fraction of said second order pump signal to generate a second output pump signal which is inserted into said second fiber length.