GaN optopairs with asymmetric spiral patterns for high-resolution 360° angle detection

Abstract

<p>This letter introduces a miniaturized angle-sensing device combining a GaN-based spiral-structured optopair with a rotating distributed Bragg reflector (DBR) sector. The optopair, fabricated through a monolithic integration process, achieves a compact size of 2.5 mm × 2.5 mm while simultaneously performing light emission and light detection. Experimental results reveal the capability of the device for 360° angle detection with a high resolution of 0.005° and microsecond-scale transient response. When incorporated with a 180°-sector DBR, the device achieves a peak photocurrent modulation of 196.4 μA, negligible hysteresis, and operational stability under high-speed rotation up to 9000 rpm. The proposed design exhibits superior performance in resolution, response time, and compactness, highlighting its potential for high-precision applications in robotics, aerospace, and automation.</p>