Coherent Tunneling by Adiabatic Passage in Silicon Nitride based Integrated Waveguide Structures

Abstract: Nowadays silicon nitride photonic integrated circuits serve as a mature platform for numerous applications. Planar waveguides and directional couplers made by CMOS-compatible technology are its basic elements. Here we demonstrate the possibilities of efficient light routing and transfer provided by the integrated planar Si3N4 waveguides structure based on the coherent tunneling by adiabatic passage (CTAP) at the 1.55um telecom band. We addressed both high- and low-confinement silicon nitride CTAP structures and proved high efficiency of light routing in them. The mechanisms that limit the light control efficiency have been revealed. The accessible parameters of such structures have been determined. Besides that, there was proposed the original hybrid Si3N4 Si - Si3N4 waveguides structure providing the enhanced efficiency and flexibility of the CTAP in comparison with the single-material Si3N4 waveguide structures.