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Journal of the Optical Society of America B

Numerical analysis of nonlinear coherent couplers exhibiting saturable index changes

Lars Thylen, Ewan M. Wright, G. I. Stegeman

Published Feb 1, 1988• 21 citations
Publisher

Abstract

Nonlinear directional coherent couplers are analyzed by using the beam-propagation method. The nonlinear media are modeled by using a saturable two-level system response. Coupler structures and excitation conditions to which the coupled-mode approach is not readily applicable are treated.
DOI
10.1364/josab.5.000467

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Two tunnel-coupled waveguides, one exhibiting positive refraction, the other exhibiting negative refraction, are analyzed. It is proposed that the positively refracting waveguide contains resonant admixture atoms, while the negatively refracting one has linear losses. The nonlinear properties of the positively refracting waveguide are related to saturation of resonance absorption. It is demonstrated that attenuation of a backward wave propagating in the studied antidirectional coupler can be compensated under certain conditions.