Real-time displacement measurement with large range and high accuracy using sinusoidal phase modulating laser diode interferometer

摘要

To resolve the conflict of large measurement range and high accuracy in the existing real-time displacement measurement laser diode (LD) interferometers, a novel real-time displacement measurement LD interferom-etry is proposed and its measurement principle is analyzed. By use of a new phase demodulation algorithm and a new phase compensation algorithm of real-time phase unwrapping, the measurement accuracy is improved, and the measurement range is enlarged to a few wavelengths. In experiments, the peak-to-peak amplitude of the speaker vibration was 2361.7 nm, and the repeatability was 2.56 nm. The measurement time was less than 26 μs.