Primary demonstration of forming interference fringes in a long distance

This paper investigates the forming of the interference fringes which are employed in long distance interferometric imaging. The characterization of the desired fringes is analyzed. The deficiencies of employing the traditional Michelson interferometer are discussed. A new optical structure to form circular symmetric fringes was proposed and an experiment was performed for verifying the new idea. A fringe pattern has been observed at a distance of 50m with a little instability, which may be caused by the small vibration of the mechanics. The experiment shows that the new optical structure is feasible.