Simulations of a High-Contrast Single-Mode Fiber Coronagraphic Multi-Object Spectrograph for Future Space Telescopes

Abstract

Directly imaging and characterizing Earth-like exoplanets is a tremendously difficult instrumental challenge. Present coronagraphic systems have yet to achieve the required $10^{-10}$ broadband contrast in a laboratory environment, but promising progress towards this goal continues. A new approach to starlight suppression is the use of a single-mode fiber behind a coronagraph. By using deformable mirrors to create a mismatch between incoming starlight and the fiber mode, a single-mode fiber can be turned into an integral part of the starlight suppression system. In this paper, we present simulation results of a system with five single-mode fibers coupled to shaped pupil and vortex coronagraphs. We investigate the properties of the system, including its spectral bandwidth, throughput, and sensitivity to low-order aberrations. We also compare the performance of the single-mode fiber configuration with conventional imaging and multi-object modes, finding improved spectral bandwidth, raw contrast, background-limited SNR, and demonstrate a wavefront control algorithm which is robust to tip/tilt errors.