This article proposes a novel demonstration of a low-loss polymer channel hybridized with a titania core leading to a nano-waveguide elongated in the normal direction to the substrate. It is aimed at using the quasi-transverse magnetic (TM) mode as the predominant mode in compact photonic circuitry. A detailed design analysis shows how a thin layer of a higher-refractive index material in a trench within the core of the waveguide can increase the confinement and reduce the propagation losses. This thin layer, produced by atomic layer deposition, covers the entire polymer structure in a conformal manner, ensuring both a reduction of the surface roughness and a stronger field confinement. The trench can be made at any place within the polymer channel and therefore its position can be tuned to obtain asymmetric modal distribution. The waveguide is demonstrated at telecom wavelengths, although the material’s properties enable operation over a large part of the electromagnetic spectrum. We measured propagation losses as low as 1.75 ± 0.32 dB/cm in a 200 nm × 900 nm section of the waveguide core. All processes being mass-production compatible, this study opens a path towards easier integrated-component manufacture.

We present an innovative waveguide based on the hybridization of a titanium dioxide nano-waveguide within a polymer strip. Through simulations and design we demonstrate that the waveguide sustains principally the quasi-TM fundamental mode and that even in tight bends (radius smaller than 2 μm) light remains confined in the titania layer. Such a waveguide, in addition of enabling low loss propagation is a way towards efficient evanescent sensing in highly integrated scheme, i.e., small footprint. We also show that the fabrication, here based on electron beam lithography and atomic layer deposition, can be extended easily to large scale manufacturing using nanoimprinting technology.