  Enabling efficient injection of light into single-mode fibers (SMFs) is a key
requirement in realizing diffraction-limited astronomical spectroscopy on
ground-based telescopes. SMF-fed spectrographs, facilitated by the use of
adaptive optics (AO), offer distinct advantages over comparable seeing-limited
designs, including higher spectral resolution within a compact and stable
instrument volume, and a telescope independent spectrograph design. iLocater is
an extremely precise radial velocity (EPRV) spectrograph being built for the
Large Binocular Telescope (LBT). We have designed and built the front-end fiber
injection system, or acquisition camera, for the SX (left) primary mirror of
the LBT. The instrument was installed in 2019 and underwent on-sky
commissioning and performance assessment. In this paper, we present the
instrument requirements, acquisition camera design, as well as results from
first-light measurements. Broadband single-mode fiber coupling in excess of 35%
(absolute) in the near-infrared (0.97-1.31{\mu}m) was achieved across a range
of target magnitudes, spectral types, and observing conditions. Successful
demonstration of on-sky performance represents both a major milestone in the
development of iLocater and in making efficient ground-based SMF-fed
astronomical instruments a reality.
