Design of high-frequency ZnO-coated optical fiber acoustoopticphase modulators

In this paper, we present a theory of an optical fiber acoustooptic phase modulator using piezoelectric zinc oxide (ZnO) coating. The effects of changing device parameters in the acoustooptic resonator are investigated for transducer design. These results are entirely different from those of the well-known; planar device structure since every part plays an important role in the resonator structure. Optical phase modulation in the frequency region up to 1 GHz is also demonstrated. Multiple sharp resonance peaks with a maximum phase shift of 0.7 radians are observed     

Electronic Feedback System for Stabilization of Fiber Ring Resonator

We propose a simple technique to stabilize the optical output intensity of a fiber ring resonator. The electronic feedback circuit system, which consists of two voltage control oscillators, a phase comparator, and a low pass filter, is applied to the fiber ring resonator in order to compensate the optical phase shift in the ring loop. The reference electrical signal determines the operating condition of the fiber ring resonator for the desired optical output signal. The experimental results within the operating range agree well with the analytical results. The simulated performance of the proposed model is also compared with that of other existing models and shows significant improvement over them.     

ZnO-coated fiber acoustooptic phase modulator

We have developed an approximate theory of all-fiber acoustooptic phase modulator using ZnO coating. The induced axial and radial strains by acoustic waves dominantly affect low- and high-frequency modulation, respectively. The prediction of the optical phase modulation agrees well with the experimental published data.