Guiding and Confining Light in Low-Index Circularly Symmetric Waveguides

A circularly symmetric waveguide with a low-index ring inside the core has been proposed and studied comprehensively. By taking advantage of the azimuthal TM01 mode, the structure can confine light inside the low-index region with very high power confinement efficiency. Key characteristic parameters as functions of geometry factors have been investigated through rigorous finite-difference methods. The fabrication tolerance and the material candidate for various potential applications have been discussed.