Photonic fractional Fourier transformer with a single dispersive device

In this work we used the temporal analog of spatial Fresnel diffraction to design a temporal fractional Fourier transformer with a single dispersive device, in this way avoiding the use of quadratic phase modulators. We demonstrate that a single dispersive passive device inherently provides the fractional Fourier transform of an incident optical pulse. The relationships linking the fractional Fourier transform order and scaling factor with the dispersion parameters are derived. We first provide some numerical results in order to prove the validity of our proposal, using a fiber Bragg grating as the dispersive device. Next, we experimentally demonstrate the feasibility of this proposal by using a spool of a standard optical fiber as the dispersive device.Fil: Cuadrado Laborde, Christian Ariel. Consejo Superior de Investigaciones Cientificas. Instituto de Ciencia de Los Materiales de Barcelona; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Investigaciones Opticas (i); Argentina. Universidad Catolica de La Plata; ArgentinaFil: Carrascosa, A.. Consejo Superior de Investigaciones Cientificas. Instituto de Ciencia de Los Materiales de Barcelona; EspañaFil: Diez, Antonio. Consejo Superior de Investigaciones Cientificas. Instituto de Ciencia de Los Materiales de Barcelona; EspañaFil: Cruz, Jose Luis. Consejo Superior de Investigaciones Cientificas. Instituto de Ciencia de Los Materiales de Barcelona; EspañaFil: Andres Bou, Miguel. Consejo Superior de Investigaciones Cientificas. Instituto de Ciencia de Los Materiales de Barcelona; Españ

Photonic fractional Fourier transformer with a single dispersive device

In this work we used the temporal analog of spatial Fresnel diffraction to design a temporal fractional Fourier transformer with a single dispersive device, in this way avoiding the use of quadratic phase modulators. We demonstrate that a single dispersive passive device inherently provides the fractional Fourier transform of an incident optical pulse. The relationships linking the fractional Fourier transform order and scaling factor with the dispersion parameters are derived. We first provide some numerical results in order to prove the validity of our proposal, using a fiber Bragg grating as the dispersive device. Next, we experimentally demonstrate the feasibility of this proposal by using a spool of a standard optical fiber as the dispersive device.Centro de Investigaciones Óptica

Моделирование распространения вихревых пучков Эрмита-Гаусса в параболическом волокне

В данной работе проводится моделирование распространения вихревых лазерных пучков, согласованных с модами Эрмита-Гаусса, через волновод с параболической зависимостью показателя преломления на основе дробного преобразования Фурье. Были рассмотрены разные порядки мод и вихревых фазовых особенностей. Обнаружено различное поведение вихревых пучков ЭрмитаГаусса при прохождении через параболический волновод в зависимости от порядков мод, в частности, может происходить нивелирование вихревой фазовой особенности

Fractional Transforms in Optical Information Processing

We review the progress achieved in optical information processing during the last decade by applying fractional linear integral transforms. The fractional Fourier transform and its applications for phase retrieval, beam characterization, space-variant pattern recognition, adaptive filter design, encryption, watermarking, and so forth is discussed in detail. A general algorithm for the fractionalization of linear cyclic integral transforms is introduced and it is shown that they can be fractionalized in an infinite number of ways. Basic properties of fractional cyclic transforms are considered. The implementation of some fractional transforms in optics, such as fractional Hankel, sine, cosine, Hartley, and Hilbert transforms, is discussed. New horizons of the application of fractional transforms for optical information processing are underlined