Water Cladded Plasmonic Slot Waveguide Vertically Coupled With Si₃N₄ Photonics

• Main Authors: George Dabos, Dimitra Ketzaki, Athanasios Manolis, Evaggelia Chatzianagnostou, Laurent Markey, Jean-Claude Weeber, Alain Dereux, Anna Lena Giesecke, Caroline Porschatis, Bartos Chmielak, Dimitris Tsiokos, Nikos Pleros
• Format: Article
• Language: English
• Published: IEEE 2018-01-01
• Series: IEEE Photonics Journal
• Subjects: Photonic integrated circuits; plasmonics; surface plasmons; directional coupling; plasmonic waveguide; silicon nitride
• Online Access: https://ieeexplore.ieee.org/document/8353831/

We demonstrate a water cladded plasmo-photonic waveguide, by exploiting the directional coupling scheme to vertically divert light from a 360 × 800 nm (height × width) Si₃N₄ waveguide to a plasmonic slot waveguide, enabling the excitation of a pure plasmonic mode within a 210-nm-wide slot at 1550 nm. The 150-nm-thick plasmonic slot waveguide was deposited on the top of an oxide cladded Si₃N₄ waveguide exhibiting an experimental plasmonic-to-photonic insertion loss of 2.24 ± 0.3 dB and a plasmonic propagation length (L_spp) of 10.8 μm at 1550 nm. The proposed plasmo-photonic waveguide holds a promise as an optical transducer element for highly sensitive and low-cost interferometric biosensors due to the significant phase change achieved per unit propagation length.