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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. © 2013 The Author(s).

An acousto-optic modulator (AOM) is used to tune the spectral properties and add a dynamic component to a long period fiber grating (LPG). Most of the physical parameters that an LPG is sensitive to, can be obtained through passive analysis of the spectral changes. Here, we show that by adding a temporal response component to the grating sensitivity, dynamic parameters such as fluid viscosity, can be extracted. By measuring the modulation signal rise time and/or the acousto-optic efficiency, we demonstrate a compact, dip-style, multi-parameter sensor, which is able to measure, among various parameters, the viscosity of a fluid in frequencies up to 700 Hz. Further, we show that taking the temporal response into consideration, the sensor has a linear response against viscosity, in contrast to average measurements based on spectral properties. The non-linear component of the average measurements arises from a relaxation of the initial acoustic perturbation on a timescale longer than the initial rise time. © 2011 Elsevier B.V.

A method for a fast and fine control of a notch filter and the control of the group delay of a fiber Bragg grating (FBG) is presented. The method is based on the acousto-optic modulation in optical fibers. © 2011 IEEE.

A flexural wave is applied to an optical fiber during the process of Bragg grating inscription using the direct writing method through a phase mask. Using this approach, we can dither the writing process to allow complex grating writing. Examples we demonstrate are tunable sampled gratings and phase-shifted gratings. © 2011 American Institute of Physics.

We have shown experimental results of the excitation of long period fiber gratings by means of flexural acoustic waves with a wavelength larger than the grating period, validated by numerical simulations. The effect of the acoustic wave on the grating is modeled with the method of assumed modes, which delivers the strain field inside the grating, then used as the input to the transfer matrix method, needed for calculating the grating spectrum. The experimental and numerical results are found to be in good agreement, even though only the strain-optic effects are taken into account. © 2011 IOP Publishing Ltd.

When an acoustic wave excites a phase-shifted fiber Bragg grating (PSFBG) several properties of the transmission/reflection spectrum, such as transmission notch depth and spectral bandwidth are influenced. In this work, a study on the effect of acoustic waves in PSFBGs is presented. The results are supported by theoretical simulation and experimental work. The technique can be used for different applications, such as in a fast tunable optical notch filter. © 2010 Elsevier B.V. All rights reserved.

A novel technique that uses flexural acoustic waves to periodically dither the fiber during grating writing is presented. Results show the fabrication of sampled structures leading to a precise control in the grating fabrication. © 2011 OSA.