本論文中使用滑輪式環型共振腔(Pulley-type ring resonator)，環的材料為金(Au)，以波導耦合來產生表面電漿共振，利用表面電漿對折射率變化特別敏感的特性來作為生醫感測器。以有限時域差分法(Finite-Difference Time-Domain Method, FDTD)來模擬電磁波在共振腔中傳播情形，並改變環半徑的大小來觀察靈敏度變化的情形。本論文中所研究之元件的靈敏度可高達602.6nm/RIU。;In this study, we study the pulley type ring resonator with the gold ring to produce surface plasmon resonance by waveguide coupling. Since the generation of the surface plasmon is particularly sensitive to the change in the refractive index, the device can be served as a biomedical sensor. The finite-difference time-domain method (FDTD) is used to solve the Maxwell’s equations to evaluate the performance of the device. The electromagnetic field distribution (EMF) inside and outside the ring resonator can be calculated by the FDTD method. By changing the ring radius, we investigate the device sensitivity. In this work, the sensitivity can be as high as 602.6nm / RIU.