Conspicuous and safe MR markers are essential for tracking interventional MRI devices. The RF induced heating on long conductors used in current active MR markers presents a safety risk. In this work, a novel acousto-optic active MR marker with optical fiber connection is proposed to eliminate RF induced heating. The proposed marker consists of a miniature coil coupled to a piezoelectric transducer which in turn modulates the reflected light in the optical fiber. The linearity of the acousto-optic active marker with flip angle is characterized and initial in vitro imaging experiments are performed demonstrating marker visibility under MRI.