Rains, AdamIreland, MichaelJovanovic, NemanjaBento, JoaoFeger, TobiasLozi, J.Schwab, ChristianCoutts, David WilliamGuyon, OlivierArriola, A.Gross, SimonHarris, Jonathan E.Simard, L.Evans, C. J.Takami, H.2019-12-182019-12-18June 10-14Adam D. Rains, Michael J. Ireland, Nemanja Jovanovic, Joao Bento, Tobias Feger, Julien Lozi, Christian Schwab, David W. Coutts, Olivier Guyon, Alexander Arriola, Simon Gross, Jonathan E. Harris, "Development of the single-mode fiber integral field unit for the RHEA Spectrograph," Proc. SPIE 10702, Ground-based and Airborne Instrumentation for Astronomy VII, 107025J (6 July 2018); doi: 10.1117/12.2314336978-151061957-90277-786Xhttp://hdl.handle.net/1885/195965RHEA is a single-mode ´echelle spectrograph designed to be a replicable and cost effective method of undertaking precision radial velocity measurements. The instrument has a novel fiber feed with an integral field unit injecting into a grid of single-mode fibers reformatted to form a pseudo-slit, increasing throughput and enabling highspatial resolution observations when operating behind Subaru and the SCExAO adaptive optics system. The past 18 months have seen a replacement cable constructed for the instrument to address modal noise caused by closely packed fibers with similar path lengths. Here we detail the cable fabrication procedure, design improvements, increased precision in meeting the required sub-micron optical tolerances, throughput gains, and known remaining issues.This work was partially funded by the Australian Research Council Discovery Project DP120103751application/pdfen-AU© 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)spectrographradial velocityoptical fibersfiber injectiondiffraction-limited spectrographhigh resolutionintegral field unit2018-07-0610.1117/12.23143362019-08-04