Long-distance optical fiber transmission system based on hybrid Raman amplification

A novel modified method for realizing long-distance self-adaptive compensation optical fiber transmission is proposed. Based on the hybrid Raman amplification achieved by combining the original bi-directional Raman pump with a second Raman amplification generated by a fiber laser formed by a fiber Bragg grating pair with high reflectivity, the signal light is amplified effectively and the longest self-adaptive compensation optical fiber transmission distance of 125 km is achieved in experiment for the first time, to the best of our knowledge. In addition, the ON/OFF gain, amplified spontaneous emission noise, noise figure and the signal power distribution characteristics of the system are studied experimentally and theoretically. The experimental results are in good agreement with the theoretical analysis.