Common-path laser encoder

This study proposes a novel common-path laser encoder (CPLE) capable of effectively minimizing environmental disturbance. The proposed CPLE uses a two-aperture phase-shifting technique to form quadrature signals. Experimental results match well with HP5529A results for long-range measurements. Results also show that the estimated measurement resolution is 0.1 ± 0.046 nm. Therefore, the proposed design has great potential for nanometer resolution and long-range applications.