volume | PIER Journals

Abstract

A fundamental relation between the cross sectional confinement of an arbitrary mode of a general waveguide and its propagation length is found. It is shown that due to material loss of the waveguide, the propagation length shrinks as the confinement of the mode increases. Normalized second central moment of magnetic energy density in the cross section plane of the waveguide is used as a measure of mode size and it is found that for a given mode size, there is a limit for the waveguide propagation length. This limit depends solely on permittivity of the waveguide material and its surrounding medium. As an application, this result provides a lower bound for propagation loss in subwavelength optical confinement in plasmonic waveguides which are of special interest for their nano-meter mode dimensions.

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Mr. Amir Arbabi

Dr. E. Arbabi

Dr. Safieddin Safavi-Naeini