Expanded-Core Planar Waveguide in Variable Optical Attenuator

Abstract

A novel structure of a variable optical attenuator is proposed. It is composed of planar waveguides as optical media and a micro-electro-mechanical system (MEMS) comb actuator with a light blocking bar as the light attenuator. The core of the planar optical waveguide is gradually expanded such that single-mode operation is maintained. The results of the analyses of the optical properties of a planar waveguide MEMS optical attenuator by an optical simulation–beam propagation method (BPM) are presented. The insertion loss, polarization-dependent loss, and wavelength-dependent loss of this attenuator are analyzed. The optimized design parameters for an expanded-core waveguide are determined through the BPM with consideration of optical losses.