F-P干涉仪差分锁频系统研究

Study on F-P interferometer differential frequency locking system

为解决法布里-珀罗(Fabry-Perot,F-P)干涉仪锁频方法响应速度、抗干扰能力、长期稳定性方面存在不足的问题,提出了F-P干涉仪差分锁频方案,将存在频差的双频激光耦合入F-P谐振腔,当激光频差足够小时,两光强信号曲线存在交叉,以两光强信号的差值作为被控量,在交叉点附近构建单调过零函数,作为闭环控制系统的反馈量,实现动态差分锁频控制。基于该方案,搭建了一套F-P干涉仪微位移测量装置并开展实验验证,结果表明该装置能够实现0~300 nm范围内的微位移测量,位移测量分辨力达到23 pm,验证了F-P干涉仪差分锁频方案的有效性,为推动微位移测量领域的发展提供了重要借鉴。

In order to solve the shortcomings of Fabry-Perot(F-P)interferometer frequency-locking method in terms of response speed,anti-interference ability and long-term stability,a differential frequency-locking scheme of F-P interferometer is proposed.Dual-frequency laser with frequency difference is coupled into F-P resonator.When the laser frequency difference is small enough,the signal curves of two light intensities will cross.Taking the difference between two light intensity signals as the controlled variable,a monotone zero crossing function is constructed near the crossing point,which is used as the feedback of the closed-loop control system to realize dynamic differential frequency locking control.Based on the scheme,a set of F-P interferometer micro-displacement measurement device was built and experimental verification was performed.The results show that the device could realize micro-displacement measurement in the range of 0~300 nm,and the displacement measurement resolution reached 23 pm,which verified the effectiveness of the F-P interferometer differential frequency-locking scheme,and provided an important reference for the development of microdisplacement measurement.