Combination Based On Raman Amplification In The Long-distance Optical Fiber Transmission System,

In recent years, because of being perfectly matched with the optical fiber system, fiber lasers can be conveniently applied to a variety of fiber-optic communications and optical fiber sensing systems. The broad application prospects and enormous technological advantages of the fiber laser technology have shown in the high-speed large-capacity WDM optical fiber communication systems, high-precision optical sensor technology and high-power laser, etc. which have attracted attention from the research and development technology from the field of electronic, industrial processing and national defense science. In this paper, the long-distance transmission system of Raman fiber laser with FBG based on the Raman hybrid amplification has been studied, and its applications in optical fiber communication have been analyzed from both theoretical and experimental. The main work can be summarized as follows:Firstly, the nonlinear effect and applications in optical fiber communications have been summarized; the characteristics of Stimulated Brillouin Scattering (SBS) threshold have been studied. The SBS thresholds of the single mode fiber of two G.652B and one G.652D are measured, the estimation formula of the SBS threshold in optical fiber has been analyzed theoretically, and the theoretical estimates and experimental measurements are in good agreement.Secondly, the principle of the Raman amplification and its application are analyzed from the theory of Raman scattering. The long-distance transmission system of Raman fiber laser with FBGs based on the Raman hybrid amplification has been constituted, which is by the use of Raman Effect generated by two pumps, and the signal light is amplified on Raman hybrid amplification. By using fiber Bragg grating to structure resonant cavity, the lasing light is generated as a secondary pump for the secondary Raman amplification to the signal light, to obtain a higher Raman gain to achieve long-distance optical fiber transmission with no loss of gain-clamped. A theoretical model of this system has been set up. The measurement experiment of the fiber Raman gain coefficient has been carried out by gain switching method. The measuring principle has been analyzed, and the experimental data and the literature value have been compared.Finally, the Raman amplifier performance parameters are analyzed. The experiment of the long-distance transmission systems of Raman fiber laser with FBGs based on the Raman hybrid amplification has been built Experimently. The system's switching gain, ASE noise, noise figure and the signal power's distribution have been measured, and the longest non-loss optical fiber transmission distance (125km) to the best of our knowledge has been achieved.The effects of gain-clamped from the theoretical model system have been studied, and the effects of the way pumped and the fiber length in the dynamic range, noise performance and the impact of non-linear damage are mainly discussed. The results show that the system as an ultra-long fiber transmission system, the effects of gain-clamped in DWDM system to overcome the signal distortion and channel crosstalk has a very good application prospects.