为了实现高速、高精度、高灵敏度、操作方便可控、稳定性好和成本较低的剩余双折射值和快轴方向角的同时测量，采用弹光调制器(PEM)和电光调制器(EOM)组合，并运用探测器探测信号和锁相放大器锁相输出一倍频项数据。直流(DC)项和倍频项数据在计算机中求解得到双折射值和方向，实现了双折射值和方向的单弹光单通道同时测量。对该新方案原理进行了分析，并搭建了实验系统。采用初始值偏移的方法对系统进行了校准，并运用该系统对Berek偏振补偿器样品进行了实验分析。实验结果表明，系统校准有效地消除了PEM和EOM的自身剩余双折射引入的测量误差；本文方案对剩余双折射值的测量精度和重复度分别优于99.16％和0.0082 rad，剩余双折射的快轴方向角测量重复度为0.06°。本文方案具有工作稳定、重复度高、测量速率快、成本相对较低和系统利于工业自动化集成等应用优势。

In order to measure the residual birefringence and direction angle of fast axis simultaneously, with the advantage of high speed, high precision, high sensitivity, easy operation, good stability and low cost, the photo-elastic modulator (PEM) and electro-optic modulator(EOM) are combined, and the detector is used to detect signals and the locked-in amplifier is used to achieve the first harmonic term. Value and direction of birefringence are solved out by the direct current (DC) term and the first term in the computer, so the simultaneous measurement of value and direction of birefringence in a single photo-elastic modulation channel are realized. The principle of the new scheme is analyzed, and the experimental system is set up. The system is calibrated by the method of instrument offset, and the experimental analysis of a Berek polarization compensator is carried out. Experimental results show that the system calibration can effectively eliminate the measurement error maybe introduced by PEM and EOM themselves. The measuring accuracy and repeatability rate of residual birefringence for this scheme are better than 99.16% and 0.0082 rad, respectively. The measuring repeatability of direction angle of fast axis is 0.06°. This scheme has the advantages of stable operation, high repeatability rate, fast measurement speed, low cost, and conducive to industrial automation integration and so on.