A low-cost, optical feedback laser range-finder with chirp-control

A new laser range finder using optical feedback interferometry and wavelength sweep has been developed. Our aim was to design a high-accuracy sensor for operation on short distances, using a low-cost Mach-Zender interferometer to separately measure the chirp of the laser. Experimentally, on a plain diffusing target, at a 10-cm distance, we were able to demonstrate an accuracy of 100 /spl mu/m. Projected accuracy is down to 20-50 /spl mu/m.