An exact theory for an optical acousto-optic phase modulator with a ZnO coating (OF-AOPM) has been developed, which is made by considering only the radial strain induced by acoustic wave in the resonator. It has been shown that radial strain alone gives strong modulation in the vicinity of a modulating frequency close to half-wave resonance of the Piezoelectric ZnO Coating. At frequency far from this region, not only radial strain but also axial strain may be counted on for optical modulation. In this paper, phase modulation in OFPM for the entire frequency region is presented by considering both axial and radial strains. The theoretical calculation shows good agreement with the experimental results. The frequency response of the OF-AOPM for optical phase modulation has been investigated using this theory. For broadband frequency responses, both radial and axial strains play important roles in optical phase modulation. At low frequencies below the vicinity of the half-wave resonant frequency of ZnO film, the axial strain is dominant. For the other frequency regions, strong phase modulation arises from the strain and the simplified theory presented in the previous paper  can be applied. This theoretical model is expected to be useful in device design as well as for many device applications.
By developing an exact theory from the device structure based on the actual cylindrical nature of the transducer, an electrical model of the optical-fiber acousto-optic fiber phase-modulator (OFPM) coated with piezoelectric ZnO has been presented. Then, full details for the acoustic transducer resonator have been investigated, which are vital
considerations in transducer design. Finally, to evaluate the validity of the model and the parameters deduced from that
model, we use the practical coefficients and parameters in theoretical calculations. An excellent agreement exists
between the model simulation results and experimental measurements.
In this paper, the Time-Frequency Differential Phase Shift Keying (TFDPSK) modulation has been presented. Firstly, the Mathematical modeling is developed. Then the circuitry modeling is investigated. Finally, the simulation of the π/2-TFDPSK signal is described. The conclusion about TFDPSK is drawn through the analysis of the power spectral density.
This paper discusses an optical fiber acousto-optic phase modulator coated with piezoelectric ZnO. The geometry of optical fiber using ZnO coating has firstly been presented and the basic theory of piezoelectric resonator of this geometry been analyzed. Also, the equivalent network model for the optical fiber acousto-optic phase modulator coated with piezoelectric ZnO has been given. And then, the reflection coefficient R<SUB>f</SUB> has been obtained by this model. Finally, calculation of R<SUB>f</SUB> has been made in great detail according to the practical parameters.