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26 February 2003 MAM testbed data analysis: cyclic averaging
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The micro-arcsecond metrology testbed (MAM) provides a testing ground for SIM to perform optical path difference measurements with picometer (pm) precision. Because of imperfect optics and non-ideal laser sources it is inevitable that the cyclic bias is one of the major error sources for SIM. Many experiments have been conducted to diagnose and to characterize cyclic bias in the laser gauges, and in white light fringe detection. Our data analysis indicates that cyclic bias in MAM has a predictable frequency and a relatively stable amplitude. It has been proposed to use phase measurements at different wavelengths to solve for the cyclic bias. The experiment results have shown that the cyclic bias in SAVV are reduced from nm level to the level of hundred picometers. Besides the cyclic bias the effective wavelengths of spectral channels have to be calibrated also. At present, a new method using FFT technique and new metrology gauge demonstrates that the wavelength determination has a precision of 10-4. The spectrometer in MAM is stable. The changes of effective wavelengths in a few weeks is about one nanometer, or less. Systematic biases above must be periodically calibrated.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Xiaopei Pan, Feng Zhao, and Michael Shao "MAM testbed data analysis: cyclic averaging", Proc. SPIE 4852, Interferometry in Space, (26 February 2003);

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