III-Nitride Optochip-in-Sphere for Dual-Axis Angle Detection

Abstract

An in-sphere GaN-based optochip for dual-axis angle detection is introduced. It comprises a cross-shaped optochip enclosed in a glass sphere with mineral oil as a liquid pendulum. The optochip monolithically integrates a light emitter and four photodetectors on a sapphire substrate. The device responds linearly to ±90° angles in both the X- and Y-axes, with sensitivities of 39 nA/° and 37 nA/°, respectively. The device exhibits fast fall and rise times of 0.143 s and 0.084 s, respectively, and a high resolution of 0.05°. Its compact configuration facilitates its applicability in human posture monitoring and robot movement detection.