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外文期刊>Journal of Modern Optics
>Polarization effects and their minimization in an infrared single-mode fibre-optic double-Fourier stellar interferometer
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Polarization effects and their minimization in an infrared single-mode fibre-optic double-Fourier stellar interferometer
In astronomical double-Fourier interferometry, stretching a single-mode fibre to generate optical path length modulation is an attractive alternative solution to the more classical bulk delay line. However, such an operation is not free from side effects, one of them being the perturbation of the radiation state of polarization by the waveguide. We present both theoretical and experimental investigations of the polarization behaviour of single-mode fibres in a double-Fourier interferometer. Changes in the state of polarization can be induced by asymmetries in the fibre parameters, and macrobending, twisting, etc., but the main cause of perturbation is the stretch of the fibre which is wrapped onto a piezoelectric tube driven by a high voltage, Not only are these fibre-stretch-in-duced polarization effects chromatic, but also they depend on the stretching state. The general consequences of the polarization perturbations for double-Fourier interferometric imaging are to distort the source's reconstructed spectral and spatial brightness distribution, depending upon the fringe detection scheme, Polarization effects can be minimized by introducing a polarization controller or better yet, as is proposed here; the fibre can be wrapped in a specific way to neutralize the perturbations.
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