Fully analog self-mixing laser vibrometer

This work concerns the implementation of a fully analog vibrometer utilizing self-mixing interferometric technique. Its working principle is a sort of unwrap of the interferometric signal: by analog elaborations the jumps of the signal are compensated. The sensor exploits the linearity of a single interferometric fringe, achieving resolution much better than half a wavelength, over a wide displacement range. The realized sensor combines a very simple optical setup with a low cost electronic elaboration, allowing excellent performances: 1 mm of range measurement with 35 nm resolution, 10 kHz bandwidth, obtained with very low material cost, including the optical and electronics components.