The Pyramid wave-front sensor (WFS) is currently the baseline for several future adaptive optics (AO) systems, including the first light systems planned for the era of Extremely Large Telescopes (ELTs). Extensive investigation into the Pyramid WFS aim to prepare for this new generation of AO systems, characterizing its behavior under realistic conditions and developing experimental procedures to optimise performance. An AO bench at Laboratoire d'Astrophysique de Marseille has been developed to

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... nalyze the behavior of the Pyramid and develop the necessary operational and calibration routines to optimize performance. The test bench comprises a Pyramid WFS, an ALPAO 9 × 9 deformable mirror (DM), a rotating phase screen to simulate atmospheric turbulence and imaging camera. The Pyramid WFS utilizes the low noise OCAM 2 camera to image the four pupils and real time control is realized using the adaptive optics simulation software OOMAO (Object Oriented Matlab Adaptive Optics toolbox). 1 Here we present the latest experimental results from the Pyramid test bench, including comparison with current Pyramid models and AO simulations. We focus on the calibration of the AO system and testing the impact of non-linear effects on the performance of the Pyramid. The results demonstrate good agreement with our current models, in particular with the addition of more realistic elements: non-common path aberrations and the optical quality of the Pyramid prism.