Digital Feedback Optical Vibrometer

Self-mixing interferometer allows to realize different kind of measuring systems, especially vibrometers. This work describes the design and implementation of a digital feedback-loop, acting on the laser pomp current, able to lock the interferometer to half-fringe, and to measure the target vibration by estimating the feedback error signal. The digital approach allows to overcome some problems of already-proposed analog feedback-loop, realizing a more reliable measurement system