Research On Nonlinear Coupling Chracteristics In Chiral Fibers

In recent years, because of the great applications as optical signal processor, sampler, pulse compression, light switches, nonlinear directional couplers have attracted a great deal of researchers'interests. At the same time, the chiral fibers possess attractive application prospects for their novel features in mode propagation. But, it is very pity that few of people has realized the greater academic value on coupling in the chiral nonlinear fibers. So it is very necessary to do research on nonlinear coupling characteristics in chiral fibers. .In this thesis, the history of nonlinear directional coupler and the development of the investigation are introduced. chirality and its classification are summarized, the method of deriving the coupled-mode in chiral fiber is introduced.In this thesis, from the linear coupled-mode equation of chiral fiber, do the research of coupling characteristics of two fibers and three fibers which have two types of relations, and then using the theory of coupled-mode, analyze the influence factors on coupling fibers. And the coupled properties of fibers are investigated. Base of the linear coupled equation of chiral fibers, the nonlinear coupling equations for chiral fibers are obtained when we considering the Kerr nonlinearity. Using the equation we having derived, the principle of continuous switch and the nonlinear effects of MZI are explored.The nonlinear coupler of chiral fiber can be used as all optical switches, once this technology has been explored, it will be a new type of fiber communication net with transmission ability.