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Proceedings Paper

Wavefront control for minimization of speckle coupling into a fiber injection unit based on the electric field conjugation algorithm
Author(s): Jorge Llop Sayson; Dimitri Mawet; Garreth Ruane; Jacques-Robert Delorme; Daniel Echeverri; Nemanja Jovanovic; Nikita Klimovich; Yeyuan Xin
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Paper Abstract

A fiber injection unit situated in the focal plane behind a coronagraph feeding a high resolution spectrograph can be used to couple light from an exoplanet to obtain high resolution spectra with improved sensitivity. However, the signal-to-noise ratio of the planet signal is limited by the coupling of starlight into the single mode fiber. To minimize this coupling, we need to apply a control loop on the stellar wavefront at the input of the fiber. We present here a wavefront control algorithm based on the formalism of the Electric Field Conjugation (EFC) controller that accounts for the effect of the fiber. The control output is the overlap integral of the electric field with the fundamental mode of a single mode fiber. This overlap integral is estimated by sending probes to a deformable mirror. We present results from simulations, and laboratory results obtained at the Caltech Exoplanet Technology Lab’s transmissive testbed. We show that our approach offers a significant improvement in starlight suppression through the fiber relative to a conventional EFC controller. This new approach improves the contrast of a high contrast instrument and could be used in future missions.

Paper Details

Date Published: 12 July 2018
PDF: 9 pages
Proc. SPIE 10703, Adaptive Optics Systems VI, 1070372 (12 July 2018); doi: 10.1117/12.2313657
Show Author Affiliations
Jorge Llop Sayson, Caltech (United States)
Dimitri Mawet, Caltech (United States)
Jet Propulsion Lab. (United States)
Garreth Ruane, Caltech (United States)
Jacques-Robert Delorme, Caltech (United States)
Daniel Echeverri, Caltech (United States)
Nemanja Jovanovic, Caltech (United States)
Nikita Klimovich, Caltech (United States)
Yeyuan Xin, Caltech (United States)

Published in SPIE Proceedings Vol. 10703:
Adaptive Optics Systems VI
Laird M. Close; Laura Schreiber; Dirk Schmidt, Editor(s)

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