Theoretical analysis on nonlinearity of optical fiber with uniaxial crystal material cladding

The effective mode area and nonlinearity of a proposed fiber with cladding made of uniaxial anisotropic crystal material are derived by fully vectorial method, the influence of kcl, the ratio of the extraordinary to the ordinary ray index, on optical field distribution and nonlinear coefficient γ is investigated theoretically. The results indicate that kcl has no impact on optical field distribution and nonlinearity at the wavelength of near 1330 nm (crossing point of the curves), but at short wavelength of below 1330 nm, the larger kcl is, the more scattering the optical mode field is. However, at the long wavelength, the conclusion is just contrary and kcl has more obvious impact on optical field distribution and nonlinearity than that at short wavelength. Thus the nonlinearity γ can be effectively modified by tailoring kcl at given other parameters of the fibers, and these results provide basis theory for designing optical communication components and optical sensors.