Novel Variable Optical Attenuator Based on Three-Dimensional Hollow Waveguide

Abstract

We propose and demonstrate a novel variable attenuator composed of a three-dimensional (3D) hollow optical waveguide with a variable air gap. We fabricated a 3D hollow waveguide with a groove in multilayer-coated plates. The displacement of a cover plate is carried out using a piezoactuator. The change of the core thickness results in variation of lateral optical confinement, which gives us variable attenuation of 14 dB.