title: General analytic expression and numerical approach for the Kerr nonlinear coefficient of optical waveguides.
abstract: The Kerr nonlinear coefficient γ is a key parameter that quantifies the nonlinear strength of an optical waveguide. For lossy waveguides such as plasmonic waveguides, the literature is confusing because various expressions derived by different groups have generally not been validated, and the conditions when they apply are not explicitly specified. Here we derive a rigorous and full-vectorial model, leading to both a general analytic expression and a general numerical approach for finding γ, as well as to their underlying relationship. Our results, exemplified by lossless and lossy waveguides, are consistent not only with each other, but also with the results in literature under appropriate limiting conditions. This work provides a benchmarked framework to understand and engineer nonlinear nanophotonic devices.
authors.forename: Guangyuan
authors.initials: G
authors.lastname: Li
authors.forename: C
authors.initials: C
authors.lastname: Martijn de Sterke
authors.forename: Stefano
authors.initials: S
authors.lastname: Palomba