光学偏振法在无创血糖检测技术中具有很好的应用前景，人眼运动引起的实时变化的双折射是偏振法无创血糖测量的主要限制因素。采用激光模拟调制与法拉第调制相结合的双调制法建立了实时闭环单波长偏振光检测系统。双调制法克服了先前由直流电压驱动激光器和法拉第调制器构成的偏振检测系统达到稳定所需时间由单一法拉第调制器的调制频率限制的问题；且系统的响应时间小于10 ms，可更为有效地克服人眼运动对测量的影响；同时双调制法可降低系统电磁干扰和激光在低频调制下的1/f 噪声，有提高系统信噪比的潜力。通过两次检测0~600 mg/dL、间隔100 mg/dL 的葡萄糖水溶液浓度对该系统的性能进行了评估，两次测量值的标准差均小于10 mg/dL ，验证了该检测系统的重复性与精确性。

Optical polarimetry for probing aqueous humor glucose concentrations has been shown as a method for ascertaining blood glucose concentrations noninvasively. One major limiting factor for polarimetric approach for glucose sensing is time-variant corneal birefringence due to motion artifact. A real-time closed-loop single wavelength polarimetric glucose sensor is designed utilizing modulation of laser simultaneously with Faraday modulation. The method overcomes the problem of previous polarimetric systems whose response speed is solely limited by the Faraday modulation frequency, when the lasers are powered by a constant direct-current voltage and the polarization is modulated using a single Faraday rotator. It makes the feedback system reach stable status within 10 ms, which should be fast enough to minimize the effect of polarization rotation due to birefringence. This approach can reduce laser noise from 1/f in addition to electromagnetic interference, improving the signal-to-noise ratio of the system at the presence of motion artifact. The system is constructed and evaluated in vitro for glucosedoped water solutions, whose concentrations are 0~600 mg/dL with increment of 100 mg/dL, the standard error of predicted results of glucose concentration is less than 10 mg/dL, demonstrating the repeatability and accuracy of the system.