A fiber feed system for a multiple object Doppler instrument at Sloan Telescope

摘要

A fiber feed system has been developed to allow a new generation multiple object Doppler instrument, called the WM Keck Exoplanet Tracker, simultaneously tracking 59 stars for high precision radial velocity measurements for planet detection, and switching among over 500 targets per night. The system includes 27 plug fiber bundles and 3 instrument fiber bundles, and each fiber bundle includes 22 fibers. Individual fibers of a plug fiber bundle are plugged to a plate to receive star lights, and then they are grouped together to form a compact 22-fiber connector. An instrument fiber bundle with a matching fiber bundle connector can connect and disconnect with the plug fiber bundle. The 45 m long instrument fiber bundles deliver the light from the telescope to an environment controlled instrument room in distance. We characterizes the light loses including the position and pointing error of plug connectors, the fiber end reflection, fiber misalignment at the mating connectors, focal ratio degradation and fiber absorption through the long fiber link. All fiber bundles are tested and average total throughput of 61% is achieved.