A single-mode Echelle spectrograph: eliminating modal variation, enabling higher precision Doppler study

Abstract

An innovative compact - yet high resolution - cross-dispersed echelle spectrograph has been designed, built, and deployed at TSU's 2-meter robotic telescope for initial tests and commissioning. This design is based on a single mode fiber (SMF) and it eliminates mode noise in fiber-fed spectrographs which is important for m/s precision exoplanet Doppler searches. The use of SMFs removes modal variation, makes the design compact and the camera focus slow and stable at the price of lower throughput. This can be improved by using adaptive optics or by placing it in space; the compact design is well suited for such deployment.