Plasmonic inverse rib waveguiding for tight confinement and smooth interface definition

Henri Benisty (1) , Mondher Besbes (1)

1 Laboratoire Charles Fabry de l'Institut d'Optique / Naphel

A plasmonic inverse rib optical waveguide geometry is proposed and investigated, inspired by the recent CdS-nanorod-on-silver plasmonic laser. The proposed technology is suitable for large scale fabrication. It only uses a single wet resist development and several coatings onto a flat metal surface to define the waveguide geometry. It thus relieves the need to etch or lift-off a noble metal. High-index sol-gel inverse ribs are privileged candidates for the tightest confinement. We investigate and explain the guidance mostly for the case of Au and the wavelengths around =633 nm. We get spot sizes down to 2560 nm2. We notably describe how easily the tigh confinement is granted and the reasons why only a single critical step defines the modal geometry. We finally detail how the classical building-blocks of integrated optics such as distributed reflectors and couplers can be made within the very same approach and integrated into devices for which losses are described.

Domaines: Optique / photonique

Henri Benisty, Mondher Besbes. Plasmonic inverse rib waveguiding for tight confinement and smooth interface definition. Journal of Applied Physics, 2010, 108, pp.063108. ⟨10.1063/1.3478746⟩. ⟨hal-00546215⟩