FIBER-OPTIC SENSORS FOR VIBRATION AND STRAIN MEASURING - A REVIEW

This article presents a brief overview of fiber-optic sensors and their development in the past 30 years. The new technologies like FBG or OTDR sensing principles have formed an entirely new generation of sensors. Some of these sensors, depending on their applications and measurands, have been successfully commercialized and they are shown in this article. Also, a multimode fiber optical sensor that measures vibrations, is presented. Multimode fiber has a relatively large number of modes that travel simultaneously through the fiber and interfere with each other. By applying various forces upon the fiber, mode's way of propagation will be changed, consequently their interference distribution will be changed, therefore generating a different field pattern at the fiber end. Difference in field pattern can be used for obtaining vibration parameters such as the amplitude and the frequency.