Enhanced phase-shifting measurement with a double-passed Michelson interferometer

A double-passed Michelson interferometer for enhanced phase-shifting measurement is described in this paper. Two interference signals concerning measurement and reference beams are generated from a common optical system simultaneously. The enhanced phase-shifting measurement can be achieved through the optimized signal difference of the measurement and reference beams, which can be easily processed and optimized on a computer. The sensitivity improvement of the interferometer by an amplification factor of 9 is experimentally demonstrated. The experimental and theoretical results are found to be in good agreement when the sensitivity ratio is less than 9.