New simple optical sensor: From nanometer resolution to centimeter displacement range

A very simple displacement sensor is presented with nanometric resolution over centimetric travel range. The compact system is composed of a laser-diode module and a photodiode array leading to a non-contact sensor. With a corner cube configuration, it is not sensitive to most of main mechanical defects of the mobile platform. The use of an optical fiber and a normalization process inspired from classical four-quadrant detectors allows high repeatability and minimal drifts. This paper exposes the setup, simulations and experimental results. Several displacements over millimeters range with a resolution of 1.2nm sustain the simulations.