Loss reduction of abrupt waveguide-bends using Fabry-Perot cavity for optical interconnects

Abstract

A novel low-loss bending structure in dielectric waveguides is proposed. In the proposed structure, an antiresonant Fabry-Perot cavity parallel to the original waveguide is added at the outer side of the bend in order to reduce the bending loss. Based on a simple design rule for the antiresonant cavity, the materials can be flexibly chosen to be adapted to fabrication methods. The beam propagation method is used to verify this low-loss design. The double-bend and curved structures using the same principle for further loss improvement are also presented.