快轴可调弹光调制器闭环稳定控制研究

Study on Closed-Loop Stability Control of Fast Axis Adjustable Photoelastic Modulator

快轴可调弹光调制器(FaaPEM)不仅具有调制频率高、通光孔径大、抗震性能好等优势,同时还弥补了传统弹光调制器相位延迟量和快轴方位角无法灵活调节的不足,在偏振调制以及偏振测量中发挥着重要的作用,FaaPEM是由两个压电驱动器和弹光晶体构成的谐振型光机电器件,在高压谐振状态下,因其自身的温度升高会导致弹光晶体谐振频率与驱动电压的频率不匹配,极大地影响了对于入射光的调制效率。为了确保FaaPEM在工作时的调制能力和稳定性达到最优效果,开展了FaaPEM的稳定闭环控制研究,提出了基于调制信号跟踪和相位调节的闭环驱动控制方法,并对FaaPEM稳定性进行了测试。测试结果表明:该系统加载反馈控制后,半波状态下稳定度达到4.18%,四分之一波状态下稳定度达到3.43%。

Fast axis ajustable photoelastic modulator(FaaPEM)not only has the advantages of high modulation frequency,large aperture,and good seismic performance,but also makes up for the shortcomings of traditional elastic optical modulator,such as phase delay and fast axis azimuth.It plays an important role in polarization modulation and polarization measurement.FaaPEM is a resonant optomechanical device composed of two piezoelectric drivers and elastic optical crystals.In the high voltage resonant state,due to its own temperature rise,the resonant frequency of elastic optical crystals does not match the frequency of driving voltage,which greatly affects the modulation efficiency of incident light.In order to ensure the optimal modulation capability and stability of FaaPEM at work,this paper carries out the research on the stable closed-loop control of FaaPEM,proposes a closed-loop drive control method based on modulation signal tracking and phase regulation,and tests the stability of FaaPEM.The test results show that the stability of the system reaches 4.18%under half wave state and 3.43%under quarter wave state after loading feedback control.