title: Variable coupling coefficient nonlinear directional couplers with self-focusing and self-defocusing nonlinearity.
abstract: Nonlinear directional couplers (NLDCs) with a variable coupling coefficient (VCC) in self-focusing and self-defocusing materials are investigated. Specifically, the Gaussian type VCC NLDCs are studied in detail. The results show that the responses of the VCC NLDCs on self-focusing and self-defocusing materials are different, especially when input power is high. The coupled-mode theory can also be used to predict the characteristics of the VCC NLDC on self-focusing material, even when input power is high.
authors.affiliation: Department of Physics, Shanghai Jiao Tong University, Dongchuan Road 800, Minhang, 200240, Shanghai, China. lgj@sjtu.edu
authors.forename: Gang J
authors.initials: GJ
authors.lastname: Liu
authors.forename: Bin M
authors.initials: BM
authors.lastname: Liang
authors.forename: Qu
authors.initials: Q
authors.lastname: Li
authors.forename: Guo L
authors.initials: GL
authors.lastname: Jin