24 July 2014 Phase tracking with differential dispersion
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Differential chromatic dispersion in single-mode optical fibres leads to a loss of contrast of the white light fringe. For the GRAVITY instrument, this aspect is critical since it limits the fringe tracking performance. We present a real-time algorithm that compensates for differential dispersion due to varying fibre lengths using prior calibration of the optical fibres. This correction is limited by the accuracy to which the fibres stretch is known. We show how this affects the SNR on the white light fringe for different scenarios and we estimate how this phenomenon might eventually impact the astrometric accuracy of GRAVITY observations.
© (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Xavier Haubois, Xavier Haubois, Sylvestre Lacour, Sylvestre Lacour, Guy S. Perrin, Guy S. Perrin, Roderick Dembet, Roderick Dembet, Pierre Fedou, Pierre Fedou, Frank Eisenhauer, Frank Eisenhauer, Karine Rousselet-Perraut, Karine Rousselet-Perraut, Christian Straubmeier, Christian Straubmeier, Antonio Amorim, Antonio Amorim, Wolfgang Brandner, Wolfgang Brandner, "Phase tracking with differential dispersion", Proc. SPIE 9146, Optical and Infrared Interferometry IV, 91461Y (24 July 2014); doi: 10.1117/12.2056410; https://doi.org/10.1117/12.2056410

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