<jats:title>Abstract</jats:title>
<jats:p>Diabetes is a typical lifestyle-related disease and blood glucose measurement plays an important role in daily health management and appropriate treatment for patients. Continuous glucose monitoring system (CGMS) is becoming common for general patients. In this paper, an optically-powered battery-less glucose sensor device with a 12 mm diameter is presented. The sensor is expected to be used for next-generation CGMS. The sensor is equipped with series-connected ultra-small photovoltaic cells as the power source. Circuit design and characterization, fabrication, and evaluation of a wireless sensor device are presented to demonstrate the feasibility of the proposed sensor architecture.</jats:p>