为了进一步提高相位调制型表面等离子体共振(SPR)测量技术的分辨率，从相差信号解调算法方面进行了优化。基于马赫-曾德尔干涉仪结构的相位调制SPR 系统中，携带传感信息的p光干涉信号与进行参考的s光干涉信号间存在着相位差。使用光电探测器和数据采集卡将两路干涉光信号采集到PC 机，再结合数学计算理论和信号处理原理，最终通过设定逻辑条件选取出较理想的波形、运用锁相的思想对参与解调的光信号进行锁定、利用信号处理原理对2路光信号进行相应的处理，分析了2路干涉光在同一时刻的相位差异。基于该相差信号解调算法，一段时间内相位差异的起伏为0.006° ，实现了4.7×10-7RIU(RIU 表示单位折射率)分辨率的折射率测量。

In order to improve the resolution of phase modulated surface plasmon resonance (SPR) measurement technology. The signal processing technology is optimized. In the differential phase SPR biosensor based on Mach-Zehnder configuration, the SPR phase can be extracted by comparing the phase difference between the interference signals of p- polarization and the reference signals of s- polarization. The 2- path interference optical signal is recevied by computer. According to the mathematical theory and signal processing knowledge, select and processing the interference optical signals. The phase difference of 2-path signal is analyzed at the same time. In the signal processing technology, the phase difference of ups and downs is 0.006°, and the sensitivity limit is 4.7×10-7 RIU.