Study on the Interaction of Optical Field and Transverse Acoustic Mode in Silicon Optical Fibers

The interaction of optical field and medium (transverse acoustic mode) leads to the inelastic scattering called forward stimulated Raman-like scattering (SRLS), the gain factor of SRLS has been theoretically studied in optical fibers with different Kerr nonlinearities and diameters. An analytical model of SRLS is established, considering all the acoustic modes. It is revealed the influence of Kerr nonlinearity on the gain and line shape of SRLS. With Kerr effect increasing, the gain of (anti-) Stokes beam increases, the line width of (anti-) Stokes beam broadens and the line shape profile on the anti-Stokes side of the pump beam are asymmetric, peak of gain deviating from central frequency shifts to lower frequency. The acousto-optic interaction is studied in microstructure fibers, Acoustic frequency variety of R₀₁ mode is against to the fiber radius with a direct ratio, the interaction of light and sound is related to fiber diameter and the largest gain factor appears at a radius of 0.58 μm.