  We describe a new system for multiple object spectroscopy and integral field
spectroscopy at near-infrared wavelengths using optical fibers. Both modes of
the SMIRFS instrument have been tested at the UK Infrared Telescope with the
CGS4 infrared spectrograph. The modular system includes a common optical system
to image the fiber slit onto the cold slit inside the CGS4 cryostat. The
multiobject mode consists of 14 interchangeable fused silica or zirconium
fluoride fibers each with a field of 4 arcsec. The integral field mode consists
of 72 fused silica fibers coupled with a lenslet array to give a contiguous
field of 6x4 arcsec with 0.6 arcsec sampling.
  We describe the performance of both modes. For the multiobject mode, the
feasibility and desirability of using fluoride fibers to extend the wavelength
range into the K-band is discussed. For the integral field mode, the
performance is compared with theoretical expectation with particular attention
to the effect of Focal Ratio Degradation in the fibers.
  These results demonstrate the feasibility of multiobject and integral field
spectroscopy in the near-infrared using lenslet-coupled fiber systems. Although
SMIRFS in an experimental system working with a spectrograph not designed for
this purpose, the throughput and uniformity of response are good. SMIRFS points
the way forward to systems with much larger numbers of elements.
