Research On Nonlinear Induced In Otptical Fiber

The third-order nonlinear effects, including self-phase modulation, cross-phase modulation, four-wave mixing, stimulated Raman scattering and stimulated Brillouin scattering, etc., have been extensively studied and applied in the high-speed, all-fiber network. However, the practical application of the total fiber in the outside interference or a certain environment, these third-order nonlinear effects under ideal conditions has been challenged.In this paper, for the external pressure, splice optical fiber, and a variety of optical fiber differences, the third-order nonlinear phenomena induced are researched. The following three parts are spread out:1.By changing low static pressure and pumping light polarization conditions in the optical fiber, nonlinear phenomena induced are studied in this paper, including the stimulated Raman scattering, four-wave mixing and continuous spectrum.First, changing the direction of linearly polarized pump light or the phase of elliptically polarized pump light and exerting the external pressure on the graded-index multimode fiber, the shift and full width at half maxium of stimulated Raman scattering spectra are researched, the probability of the anti-Stokes light is observed. In addition, under the same the pumping light conditions and external pressure conditions, stimulated Raman scattering, four-wave mixing and continuous spectrum phenomenon are studied in standard single-mode fiber.2. Two kind of fiber splice point is studied how to affect the non-linear effects and beam mode.With the emergence and increasment of four-wave mixing, stimulated Raman scattering spot mode changes from LP01mode to LP11mode in non-zero dispersion shifted fiber. After the beam passes through the splice segment of non-zero dispersion shifted fiber and standard single-mode fiber, LP11mode is evolved into the LP01mode again, the four-wave mixing weakens and disappears, the stimulated Raman scattering holds major intensity.3. The nonlinear spectroscopy is studied by femtosecond pulsed pump light in a standard single-mode fiber and a polarization maintaining single-mode fiber respevtively, because of several nonlinear effects above-mentioned, their transmission spectra are different.The frequency of femtosecond pulse occur the red shift and blue shift, mainly redshift in standard single-mode, but mainly blue shift in standard single-mode fiber.In this paper, these researches will contribute to the development of new fiber-optic sensor and the development and application of optical soliton communication.