The GRAVITY Coudé Infrared Adaptive Optics (CIAO) system for the VLT Interferometer by Kendrew, S, Hippler, S, Brandner, W, Clénet, Y, Deen, C, Gendron, E, Huber, A, Klein, R, Laun, W, Lenzen, R, Naranjo, V, Neumann, U, Ramos, J, Rohloff, R, Yang, P, Eisenhauer, F, Fedrigo, E, Suarez-Valles, M, Amorim, A, Perraut, K, Perrin, G, Straubmeier, C