Improving the Signal to Noise Ratio of a Fiber Optic Laser Doppler Vibrometer

In this paper possible ways of increasing the signal to noise ratio of a laser Doppler vibrometer with fiber optic components are discussed, in order to improve its metrological characteristics and to enlarge its field of possible industrial applications. System improvements, related to the frequency shifting block of the vibrometer, to its photodetector stage and to the optical head, which recovers the light scattered by a vibrating target, have been experimentally evaluated. It must be noticed that this activity has been carried out taking into account the requirement of simplicity and handiness of the measurement system and using solutions from both an optical and an electronic point of view, which are inexpensive as much as possible