PIONIER: combining 4 telescopes of the very large telescope interferometer using a photonics beam combiner

PIONIER (Precision Integrated Optics Near-infrared Imaging ExpeRiment) is a visitor instrument that performs the interferometric beam combination in the near infrared of the light delivered by the 4 main telescopes (8m) or auxiliary telescopes (1.8m) of the VLTI on the ESO Paranal site (Chile). The heart of the instrument is a photonics device optimized for H band operation (1.5 - 1.8μm) that was developed at LETI in collaboration with IPAG (formerly LAOG). This silica-on-silicon integrated optics component splits the signals coming from the 4 telescopes and recombines them, providing for each of the 6 baselines 4 phase states, thanks to integrated phase shifting functions, for a total of 24 outputs. The overall component transmission over the complete H band is 65%. These outputs are imaged on a PICNIC IR camera.