Modeling of light intensity-modulated fiber-optic displacement sensors

Light-intensity-modulated displacement sensors are currently extensively used in numerous applications. Most such sensors operate by utilizing a pair of adjacent optical fibers and a reflector. This scheme can provide a good sensing outcome, but its performance can be enhanced with the use of only a single optical fiber. Such displacement sensors have the benefits of higher sensitivity and operating range, because they can efficiently collect more light after a reflectance has occurred. Hence, this paper investigates a single optical fiber that emits and collects light while translating and rotating with respect to the main axis of the optical fiber. The Gaussian light-sensing behavior of these two cases is mathematically modeled, giving sensing characteristics such as linearity and sensitivity. Experimental results are presented for verification and validation of the models.