Browsing by Author "Anguita, Jaime A."

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    33
    (33, 33) Cisternas, Jaime E.; Anguita, Jaime A.; 33
    We propose the use of orbital angular momentum (OAM) states to form modulation symbols in a free-space laser communication link affected by atmospheric turbulence. A collection of superpositions of 2 and 4 active OAM modes are used for transmitting digital information. To sense and decode the data we compare three candidate architectures, based on a Mode Sorter, a Shack-Hartmann and phase flattening holograms. In this work we use concepts of Optimal Transport, particularly the Wasserstein distance and barycenter, for an optimal selection of OAM superpositions and a more appropriate processing of OAM spectra, leading to more accurate detection, achieving a classification error smaller than 1/1000 in intermediate to strong turbulence conditions.
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    (33, 33) Cisternas, Jaime E.; Espinoza, Javier I.; Anguita, Jaime A.; 33
    When propagated through atmospheric turbulence, Orbital Angular Momentum (OAM) modes suffer a loss of orthogonality that can compromise their detection and classification. The problem is more challenging when user information encoded on multi-state OAM superpositions needs to be detected with high probability. Optical sensors like the Shack-Hartmann detector or the Mode Sorter are candidates for such task. We describe how OAM histograms derived from such detectors can be used for decoding the original data symbols. We propose Machine Learning strategies for a reliable classification of the histogram patterns obtained with 4-mode superpositions propagated over a 1 km range in weak to intermediate turbulence.
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    (33, 33) Anguita, Jaime A.; Cisternas, Jaime E.; 33
    The increase of data rate and bandwidth efficiency of free-space optical communication links may be supported by the use of dense orbital angular momentum (OAM) states, carrying several information bits per transmission. Using machine-learning decoding, the performance of 32-OAM and 64-OAM signal constellations –designed using 4-state superpositions– are studied using numerical propagation models. Using two candidate architectures for detection –Shack-Hartmann and Mode Sorter– we evaluate the performance of the modulation in a simulated optical atmospheric channel by means of the detection accuracy.
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    Turbulence strength experimental measurements for improved detection in free space optical communications
    (SPIE) Pirela, Carlos S.; Anguita, Jaime A.; Cisternas, Jaime E.; van Eijk, Alexander M.J.; Huerta-Viso, Ariadna I.