本研究目的在於，以表面電漿共振生化感測器為基礎，設計一套高感度、低雜訊及高解析度之正交干涉生化感測系統。 這套新穎的系統可維持原本表面電漿共振裝置之高靈敏度以及高解析度，採用分佈式回饋雷射二極體(DFBLD)為光源，採用正交干涉光路，合成外差式的訊號處理，載波過濾低頻雜訊，可得線性的高訊雜比(signal to noise)相位差訊號。The purpose of this research is to design a high-sensitivity, high resolution and low noise system of a surface plasmon resonance (SPR) biosensor. In this paper, a Distributed Feed-back Bragg laser diode (DFBLD)was used as a light source, and quadrature interferometry technique was also used to setup the optical system. A synthetic heterodyne signal process was then developed to deal with the signal data. In this novel system, it preserves the advantages of high sensitivity and high resolution quality of SPR biosensor. A high signal to noise(S/N) ratio and linear data of phase difference were obtained by signal processing to filter the low frequency noise.