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We have built and commissioned a prototype agitated non-circular core fiberscrambler for precision spectroscopic radial velocity measurements in thenear-infrared H band. We have collected the first on-sky performance and modalnoise tests of these novel fibers in the near-infrared at H and K bands usingthe CSHELL spectrograph at the NASA InfraRed Telescope Facility (IRTF). Wediscuss the design behind our novel reverse injection of a red laser forco-alignment of star-light with the fiber tip via a corner cube and visiblecamera. We summarize the practical details involved in the construction of thefiber scrambler, and the mechanical agitation of the fiber at the telescope. Wepresent radial velocity measurements of a bright standard star taken with andwithout the fiber scrambler to quantify the relative improvement in theobtainable blaze function stability, the line spread function stability, andthe resulting radial velocity precision. We assess the feasibility of applyingthis illumination stabilization technique to the next generation ofnear-infrared spectrographs such as iSHELL on IRTF and an upgraded NIRSPEC atKeck. Our results may also be applied in the visible for smaller core diameterfibers where fiber modal noise is a significant factor, such as behind anadaptive optics system or on a small < 1 meter class telescope such as is beingpursued by the MINERVA and LCOGT collaborations.

Precision near-infrared radial velocity instrumentation II: Non-Circular Core Fiber Scrambler