Raman Scattering And Parametric Amplification In Single-Mode Birefringence Dispersion-Decreasing And Dispersion Shifted Fiber

Frequency conversion in birefringent optical fiber is mainly determined by competition between parametric amplification and Raman scattering. Based on this, According to the Small-signal coupling differential equations of the Stokes and Anti-stokes, we consider the pump wave is linearly polarized and aligned with the x-axis direction. Derived from Energy and the gain coefficient for the Stokes and Anti-stokes which simultaneously act of stimulated Raman scattering and Parametric amplification in the same x polarization, we have studied that gain changes with related variables in dispersion-decreasing and dispersion shifted fiber.First of all ,in dispersion-decreasing fiber, We have studied that gain changes with mismatchΔk2 and normalized distance z/L in Dispersion-decreasing fiber. The conclusion shows that gain coefficient changes with the mismatchΔk2 is Symmetrical when Non-linear coefficientγ=0, in normal dispersion regime and anomalous dispersion regime. The gain will arise a peak and then with theΔk2 and z/L increases gradually reduced in the anomalous dispersion regime when non-linear coefficientγ≠0. At the same time we have studied that feature about the ratio of Stokes and anti-stokes |Eax/Esx| with mismatchΔk2 increases rapidly reduced.According to dispersion shifted fiber(First order dispersion coefficientβ2=0), The conclusion shows that gain coefficient changes with the Frequency shift is Symmetrical in -Ωand +Ωrange when Non-linear coefficientγ=0, the number of peak changes with the changes inβ4 and P values, at the same time affecting the size and stretching the length of the peak when non-linear coefficientγ≠0. We have studied that feature about the ratio of Stokes and anti-stokes |Eax/Esx| with Frequency shift increases rapidly reduced.Through the discussion of the two optical fiber, studying parametric amplification and the role of Raman gain coefficient together change with the relevant parameters, it is a practical significance to optical switching and frequency conversion.