Study of Tunable Polarization Separator Using of Interaction Technique between Ultrasound Waves and Laser

Abstract

Many applications in physics and communications need to separate the polarization of a light wave into the two fundamental components. We mention, for example, spectral analyzers, devices for measuring and analyzing light polarization, and the technique of doubling the transmission rate on optical fibers using the property of light polarization.

Currently, passive optical elements are used to separate polarization, which depend on sticking prisms with their optical axes perpendicular, such as (Rochon Prism) and (Nicol Prism). However, the use of negative optical elements to separate the polarization is accompanied by several technical problems, including the inability of these elements to select a specific wavelength, and there is no possibility to control the intensity of the light beam in the output of the polarization separator of the negative type.

The research proposes the use of the technique of interaction between ultrasound and optical waves within a mono-axial optical crystal and proves the effectiveness of using this technique to solve the problem. The research relied on the design of the polarization separator on the crystal of tellurium dioxide (TeO₂)as a reaction medium, an ultrasound transducer was used that generates transversely polarized ultrasound waves whose propagation speed within the crystal can be controlled. The numerical and design calculations of the polarization interval were performed on a crystal (TeO₂). The effectiveness and importance of the proposed technique for separating the polarization of two signals carried on the same wavelength were mathematically demonstrated in this research. Where the first channel is transmitted on the horizontal polarization of the optical carrier and the second on the vertical polarization of the same carrier through an optical fiber, which necessitates the separation of the two signals from each other at the receiving side by means of an effective polarization separator, and therefore the commercially marketed passive prisms are unable to accomplish the porpoise.