以单束正交线偏振光为光源，利用索列尔-巴比涅相位补偿器使相位连续变化，采用锁相放大器进行数据采集，设计了一种由光纤耦合输出的窄频半导体激光器和双声光调制器组成的共线外差干涉系统，对其相位特性进行了研究，分析了激光束漂移及光源谱线宽度对相位测量的影响.实验表明：系统的相位分辨率为0.3611 μm，相位灵敏度为27.386°/mm，测量误差为0.090 rad；可以消除由声光调制器光强调制引起的相位误差，抑制激光束漂移引起的误差，以及减弱环境因素产生的噪声对测量结果的影响.

Using a pair of orthogonally linearly polarized beams as the light source, the Soleil-Babinet compensator to offer a continuous phase retardation and a lock-in amplifier as the data collector, a collinear heterodyne interferometer system was presented, which is consisted of a narrow band semiconductor laser with fiber-coupled output and two acousto-optic modulators. The phase characteristics of this system were researched and the influence of the laser beams drift, amplitude modulation and laser line width on the phase measurement was analyzed. The results show that the phase resolution is 0.3611 μm, the phase sensitivity is 27.386°/mm, and the measurement error of this system is 0.090 rad. And this system we proposed can eliminate the affect of the amplitude modulation of acousto-optic modulator and the error caused by laser beam drift. Because the two beams are perfectly collinear, the noise resulting from the environment is also reduced.