Advances and new applications using the acousto-optic effect in optical fibers

This work presents a short review of the current research on the acousto-optic mechanism applied to optical fibers. The role of the piezoelectric element and the acousto-optic modulator in the excitation of flexural and longitudinal acoustic modes in the frequency range up to 1.2 MHz is highlighted. A combination of the finite elements and the transfer matrix methods is used to simulate the interaction of the waves with Bragg and long period gratings. Results show a very good agreement with experimental data. Recent applications such as the writing of gratings under the acoustic excitation and a novel viscometer sensor based on the acousto-optic mechanism are discussed

Terahertz Kerr nonlinearity analysis of a microribbon graphene array using the harmonic balance method

Transmission spectra of microribbon graphene arrays are investigated with a circuit model based on the transmission line method. The accuracy of the proposed method is comparable with full-wave electromagnetic simulation results versus chemical potential, incident angle, dimensions of microribbons and the permittivity of the substrate. This rigorous method takes less than a second to perform, therefore it can be employed to optimize other similar devices instead of numerical methods that involve heavy calculations. Furthermore, we depicted the Kerr effect with the harmonic balance method through calculating the parameters in steady state. The results of this novel approach exhibited an excellent agreement with full-wave simulation results