ELT-HIRES the high resolution spectrograph for the ELT: fiber link

Abstract

ELT-HIRES is the high resolution and ultra-stable Echelle spectrograph for the ELT. It has been conceived as a modular instrument provided with two independent spectrometers (the baseline design) and a possible extension to four, each of them optimized to cover a fixed spectral range. The role of the fibers is essential to provide the required ultrastability. Placed at the Nasmyth focus of the ELT, the HIRES fiber link transfers the light from the focal plane to the spectrographs. Each observing modes will be use a unique and independent group of fibers (bundle). The HIRES modular design makes it possible to have new observing modes just with the addition, removal or change of the specific bundles. From a functional point of view the HIRES fiber link subsystem performs some other important tasks, such as dicing the field of view, improving the system stability and providing a uniformly illuminated slit for spectrographs. It is a key subsystem for the instrument and represents a significant technological challenge. The technical requirements, conceptual design and technologies to be used are discussed in this paper. The current status of the subsystem, and future plans are also addressed.