Embedded air core optical nano-waveguides

Abstract

We propose a nanometer-scale hollow core waveguide that can be fabricated with standard methods on a silicon-on-insulator substrate. High optical confinement in the core is possible, making such a waveguide structure suitable for sensing applications, applications making use of strong optical nonlinearities, and optofluidics applications. We extend a historical method (Marcatili's method) to provide analytical solutions for field distributions in the device and simulate power confinement, intensity, and parametric dependencies with beam propagation and finite-difference time-domain methods for two polarizations. In an example worked out, the optical confinement in the air core is ̃40% of the total waveguide power, which is favorable to that of a standard slot waveguide. The intensity per μm2 in the hollow core is 95% higher than in the silicon cladding region, indicating that avoiding optical nonlinearities is also possible. © 2010 Optical Society of America.