Experimental Research on Piston Detecting Method for Optical Synthetic Aperture Systems

For optical interference, piston error detection influences the accuracy of piston compensation considerably. We build an optical experimental system and choose dispersed fringe sensing(DFS) as piston detection method. Through numerical simulations and experiments, we find the piston within a wavelength has a linear relationship with longitudinal intensity peak offset of dispersed interference fringes. In our experiment, we use white light source(100nm spectral width) to generate dispersed interference fringes. The piston will be introduced intentionally by moving beam splitter platform. We find there is a difference between simulation results and experimental results. Then, we analyze the influence of some experimental parameters on piston detection accuracy. Finally, we find the pitch movement disturbance of beam splitter platform is the main reason of the difference.