Displacement measurement based on Fourier transform method with external laser cavity modulation

摘要: Smart optical sensors for the displacement measurement in submicron, have been developed by using self-mixing effect of a laser diode. In this article, we propose new type interferometry (SMI) to measure microscopic displacement. The phase SMI signal is modulated with external cavity length and demodulated Fourier transform analysis technique. Some errors method are discussed. We demonstrated system remote target. experiment results reveal that extraction error ∼2π×10−3 rad, approximately 8 nm.