When testing the optical surface errors with an interferometer, it is always important to determine the residual errors in
the interferometer optics. The calibration of reference optic for proper accuracy is very important issue if the precise
phase measurement results are to be obtained using interferometer. A simple ball calibration method is discussed and the
sufficient number of measurements for the ball averaging calibration is determined. Further we analysis some errors,
which limit the performance of the calibration method by using a combination of both ray optics and wave optics
This paper describes a specific criteria used for structural design in high stability required activity such as Inertial
Confinement Fusion (ICF). The specific criteria is based on coupled motion existing in optomechanical systems.
Compared to the generic criteria, compliance with the specific ones can guarantee an equally good structural
stability and relax the requirement on fundamental frequency for optomechanical system in ICF laser facility.