Cost-Efficient Distributed Amplification in a Bidirectional Optical Fiber Link

We propose and demonstrate a novel technique to implement distributed amplification in a bidirectional link. Multiple optical signals are transmitted in a duplex configuration over a single fiber. The multiple channels are generated using only two optical sources on each side of the link. Distributed amplification is achieved using Raman scattering where the data modulated signal in the downlink direction acts as a pump signal as well. To obtain maximum Raman gain and to minimize Rayleigh scattering, the difference between the center frequencies of the downlink and uplink signals is kept at 13 THz. The resulting bit-error-rate plots show low values of receiver sensitivities.