Proceedings Article | 15 October 2012
Proc. SPIE. 8417, 6th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment
KEYWORDS: Mirrors, Modulation, Interferometers, Calibration, Laser applications, Demodulation, Vibrometry, Signal processing, Homodyne detection, Signal detection
Online calibration technique for a long-baseline laser interferometer has been studied, which can be used for nanoscale
displacement and vibration measurement. The method combined laser interferometer calibration with measurement to
meet the needs of online calibration and state detection of long-baseline laser interferometer. Based on Phase Generated
Carrier (PGC) demodulation technique, we add a calibration signal which we have already known to phase-modulated
carrier, and according to the amplitude variations of calibration signal, we can achieve work condition monitoring of
laser interferometer and measurement of environmental changes and the instruction of fluctuations. In the paper, a laser
interferometer with 22-meter-long arm, resolution of 20pm and frequency range of DC ~ 200Hz used for displacement
and vibration measurement was constructed, completed the online calibration software and hardware design,
experimental results show that: by adding a calibration signal with frequency of 400Hz, amplitude 600nm, online
condition monitoring of the laser interferometer can be realized. The advantages of this method is,that it can achieve
online calibration for laser interferometer without increase burden in hardware, simplify the interferometer debugging
process, improve operational efficiency, at the same time, it is of great significance and value to practical application of
long-baseline laser interferometer .
