We report on the design of micro-ring resonator optical sensors for integration on what we call optical printed
circuit boards (O-PCBs). The objective is to realize application-specific O-PCBs, either on hard board or on
flexible board, by integrating micro/nano-scale optical sensors for compact, light-weight, low-energy, high-speed,
intelligent, and environmentally friendly processing of information. The O-PCBs consist of two-dimensional
planar arrays of micro/nano-scale optical wires, circuits and devices that are interconnected and integrated to
perform the functions of sensing and then storing, transporting, processing, switching, routing and distributing
optical signals that have been collected by means of sensors. For fabrication, the polymer and organic optical wires
and waveguides are first fabricated on a board and are used to interconnect and integrate sensors and other micro/
nano-scale photonic devices. Here, in our study, we focus on the sensors based on the micro-ring structures.
We designed bio-sensors using silicon based micro-ring resonator. We investigate the characteristics such as
sensitivity and selectivity (or quality factor) of micro-ring resonator for their use in bio-sensing application. We
performed simulation studies on the quality factor of micro-ring resonators by varying the radius of the ring
resonators and the separation between adjacent waveguides. We introduce the effective coupling coefficient as a
realistic value to describe the strength of the coupling in micro-ring resonators.