Optical load sensors utilizing fiber-Bragg-grating based Fabry-Perot resonators

We report novel optical load sensors utilizing fiber Bragg grating based Fabry-Perot (FBG-FP) structures. Each transmission peak of a FBG-FP is observed to split into two peaks due to the birefringence effect caused by the transversal loading. Transversal loading can be measured through the wavelength separation of the peak split, which shows a good linear relationship. We also demonstrate a load sensing scheme based on the measurement of the beating frequency of a dualwavelength laser employing a FBG-FP. Such a scheme also provides a new way to generate microwave signals.