21 July 2010 The Fiber Coupler subsystem of the future VLTI instrument GRAVITY
Author Affiliations +
Abstract
We present the Fiber Coupler subsystem of the future VLTI instrument GRAVITY. GRAVITY is specifically designed to deliver micro-arcsecond astrometry and deep interferometric imaging. The Fiber Coupler is designed to feed the light from a science and a reference object into single-mode fibers. The Fiber Coupler consists of four independent units. The units de-rotate the FoV. A motorized half-wave plate allows rotating the liner polarization axis. Each unit provides actuators for fast piston actuation, tip-tilt correction and pupil stabilization for one of the beams from four VLT telescopes. The actuators are operated in closed-loop. Together with a dedicated Laser Guiding System, this allows to stabilize the beams and maximize the coherently coupled light. The fast piston actuator provides the crucial fringe tracking capability at a bandwidth of >220Hz. A special roof prism design allows to either split the FoV or to serve as a 50/50 beam splitter without changing the optical path. This offers the possibility of on-axis as well as off-axis fringe tracking. The optical train consists solely of mirrors, which ensures an achromatic behavior and maximum throughput. The sophisticated optical design compensates for aberrations which are introduced by off-axis parabolic mirrors. This allows to achieve Strehl ratios of >95% across the FoV.
© (2010) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
O. Pfuhl, O. Pfuhl, F. Eisenhauer, F. Eisenhauer, M. Haug, M. Haug, M. Thiel, M. Thiel, S. Kellner, S. Kellner, A. Amorim, A. Amorim, W. Brandner, W. Brandner, J. P. Berger, J. P. Berger, K. Rousselet-Perraut, K. Rousselet-Perraut, G. S. Perrin, G. S. Perrin, C. Straubmeier, C. Straubmeier, S. Gillessen, S. Gillessen, H. Bartko, H. Bartko, A. P. Gräter, A. P. Gräter, } "The Fiber Coupler subsystem of the future VLTI instrument GRAVITY", Proc. SPIE 7734, Optical and Infrared Interferometry II, 77342A (21 July 2010); doi: 10.1117/12.857506; https://doi.org/10.1117/12.857506
PROCEEDINGS
8 PAGES


SHARE
RELATED CONTENT

JouFLU upgrades to the fiber linked unit for optical...
Proceedings of SPIE (July 23 2014)
MCAO with LINC NIRVANA at LBT preparing for first...
Proceedings of SPIE (September 01 2016)
ESPRESSO front end opto-mechanical configuration
Proceedings of SPIE (September 23 2012)
The LINC-NIRVANA testbed Fizeau interferometer
Proceedings of SPIE (October 19 2004)
GRAVITY: beam stabilization and light injection subsystems
Proceedings of SPIE (September 11 2012)
An optical fiber-based high contrast imager
Proceedings of SPIE (September 14 2011)

Back to Top