Abstract

Various kinds of fringe-counting interferometer have been successfully used for line standard calibration and precision positioning, etc. The accuracy of these systems has been claimed to within one ten-millionth or so in many papers. Although the description of error sources and evaluation of measurement accuracy was the main part of these papers, the strict relationship among the errors has not yet been clearly revealed. The reason is simply that for a fringe-counting interferometer two boundary conditions should be considered: the original optical path difference between reference and measurement arms is usually not equal to zero, and the interference order corresponding to the original path difference is set at zero at the beginning of the measurement.

© 1986 Optical Society of America