We present measurements of how multimode fiber focal-ratio degradation (FRD) and throughput vary with levels
of fiber surface polish from 60 to 0.5 micron grit. Measurements used full-beam and laser injection methods at
wavelengths between 0.4 and 0.8 microns on 17 meter lengths of Polymicro FBP 300 and 400 μm core fiber.
Full-beam injection probed input focal-ratios between f/3 and f/13.5, while laser injection allowed us to isolate
FRD at discrete injection angles up to 17 degrees (f/1.6 marginal ray). We find (1) FRD effects decrease as grit
size decreases, with the largest gains in beam quality occurring at grit sizes above 5 μm; (2) total throughput
increases as grit size decreases, reaching 90% at 790 nm with the finest polishing levels; (3) total throughput
is higher at redder wavelengths for coarser polishing grit, indicating surface-scattering as the primary source of
loss. We also quantify the angular dependence of FRD as a function of polishing level. Our results indicate that
a commonly adopted micro-bending model for FRD is a poor descriptor of the observed phenomenon.
We describe the design, construction, and expected performance of two new fiber integral field units (IFUs) -
HexPak and GradPak - for the WIYN 3.5m Telescope Nasmyth focus and Bench Spectrograph. These are the
first IFUs to provide formatted fiber integral field spectroscopy with simultaneous sampling of varying angular
scales. HexPak and GradPak are in a single cable with a dual-head design, permitting easy switching between
the two different IFU heads on the telescope without changing the spectrograph feed: the two heads feed a
variable-width double-slit. Each IFU head is comprised of a fixed arrangement of fibers with a range of fiber
diameters. The layout and diameters of the fibers within each array are scientifically-driven for observations
of galaxies: HexPak is designed to observe face-on spiral or spheroidal galaxies while GradPak is optimized
for edge-on studies of galaxy disks. HexPak is a hexagonal array of 2.9 arcsec fibers subtending a 40.9 arcsec
diameter, with a high-resolution circular core of 0.94 arcsec fibers subtending 6 arcsec diameter. GradPak is a
39 by 55 arcsec rectangular array with rows of fibers of increasing diameter from angular scales of 1.9 arcsec to
5.6 arcsec across the array. The variable pitch of these IFU heads allows for adequate sampling of light profile
gradients while maintaining the photon limit at different scales.