4-inch Fizeau interferometer transfer function measurement method

This paper conducts research on the instrument transfer function(ITF) of a 4-inch Fizeau interferometer. It first introduces the concept and principle of the ITF and investigates its measurement methods. Experimental measurements and analyses are carried out on the 4-inch Fizeau interferometer, utilizing both sinusoidal grating and simulated grating to compare and analyze the test results of the ITF. Furthermore, an error analysis is conducted based on these results.