Numerical Analysis of a Symmetric Nonlinear Directional Coupler

Hiroshi MAEDA  Kiyotoshi YASUMOTO  

IEICE TRANSACTIONS on Electronics   Vol.E77-C   No.2   pp.298-302
Publication Date: 1994/02/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Opto-Electronics
nonlinear directional coupler,  optical switching,  critical power,  finite-difference beam propagation method,  

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The power transfer characteristics of a symmetric nonlinear directional coupler (NLDC) are analyzed rigorously using the beam propagation method based on the finite difference scheme. The NLDC consists of two linear waveguides separated by a Kerr-like nonlinear gap layer. The change of nonlinear refractive index along the coupler is precisely evaluated by making use of the second-order iteration procedure with respect to a small propagation length. For the incidence of TE0 mode of the isolated linear waveguide, the highly accurate numerical results are obtained for the behavior of power transfer, and the coupling length and critical power for optical switching. The dependencies of the coupling length and critical power on the width of the gap layer and the input power levels are discussed, compared with those predicted by the coupled-mode approximations.