Stimulated Brillouin Scattering Effect Induced By High Correlative Pulse In Optical Fiber

As the fiber hydrophone system is developing to large scale array, it is important to obtain enough incident light power of the fiber hydrophone system. In fact, as the fiber has the character of special low loss and small size of effective area, high light power density can be achieved in the fiber through low incident light power, which result in nonlinear effects affecting the operation of the system. Among those nonlinear effects, Stimulated Brillouin Scattering has the worst effects on the fiber hydrophone system due to its low threshold and it produces a new light wave which is different from the incident light in frequency.This dissertation discusses the physical mechanism and quantum explanation of SBS in fiber. First, we introduce the seed initiation of SBS model to get the couple equations, which describes the SBS with Stokes seeded in fiber. Then we analyze the static character of SBS to obtain the SBS gain factor and threshold under continuous wave and pulse. Because there is no Stokes seed in fiber hydrophone system, we analyze the SBS based on the noise initiation of SBS model .We use the finite differential time domain method to do the SBS numerical simulation in fiber. We observe the SBS in single model fiber under both continuous wave and pulse. Through analyzing the experimental data, we obtain the character of SBS and verify the threshold equation. We find that the Brillouin shift is 0.08nm , which agrees well with the theoretic value. At last we observe the effects of SBS on the interferential signal.