| Magneto-optical nonlinear fibers, as a class of special fibers, possess themagneto-optical and nonlinear effects at the same time. The coupled-mode theory forguided optical waves in the magneto-optical nonlinear fibers has an practicalsignificance for designing and developing the magnetically controlled optical fiberinformation processing devices. The research works are as follows:1. According to the perturbation theory for guided optical waves, with themagneto-optic and nonlinear effects as perturbation, the coupled-mode equations for thedegenerate and non-degenerate magneto-optical four-wave mixing (MO-FWM) arederived. The parametric processes in the isotropic magneto-optical nonlinear fiber areanalytically investigated, and the phase matching condition can be magneticallycontrolled by means of the wavelength dependence of the magneto-optic couplingcoefficient.2. The influence of the magneto-optical effect on four wave mixing isexperimentally investigated, and the polarization dependency of FWM is also measured.It is shown that the magnetic controllability of FWM can be identified easily for thecase with orthogonal states of polarization. The MO-FWM effect can also be applied tomagnetic field measurement in the different operating range. The FWM efficiency canbe further improved under an appropriate bias magnetic field.3. In the case that the wavelength dependency of fiber Verdet constant is negligible,the magnetic control characteristics of fiber parametric gain are analyzed for theleft-handed circular polarization incident to the birefringent fiber. The necessity of usingmagneto-optic and nonlinear fiber with high Verdet constant in the experiments ispointed out. The maximal parametric gain can be obtained by optimizing the magnitudeof fiber birefringence, and the magnetic adjustability of parametric gain can beimproved by appropriately choosing fiber length, pump power and optical states ofpolarization.4. For the case with orthogonal states of polarization, the dependence of FWM onthe non-uniform magnetic field of "unipolar" or "bipolar" distribution are respectively studied, especially for the influence of the duty ratio of magnetic field. |
