  The Keck Planet Imager and Characterizer (KPIC) is a series of upgrades for
the Keck II Adaptive Optics (AO) system and the NIRSPEC spectrograph to enable
diffraction-limited, high-resolution ($R>30,000$) spectroscopy of exoplanets
and low-mass companions in the K and L bands. Phase I consisted of single-mode
fiber injection/extraction units (FIU/FEU) used in conjunction with an H-band
pyramid wavefront sensor. Phase II, deployed and commissioned in 2022, adds a
1000-actuator deformable mirror, beam-shaping optics, a vortex coronagraph, and
other upgrades to the FIU/FEU. The use of single-mode fibers provides a gain in
stellar rejection, a substantial reduction in sky background, and an extremely
stable line-spread function on the spectrograph.
  In this paper we present the results of extensive system-level laboratory
testing and characterization showing the instrument's Phase II throughput,
stability, repeatability, and other key performance metrics prior to delivery
and during installation at Keck. We also demonstrate the capabilities of the
various observing modes enabled by the new system modules using internal test
light sources. Finally, we show preliminary results of on-sky tests performed
in the first few months of Phase II commissioning along with the next steps for
the instrument.
  Once commissioning of Phase II is complete, KPIC will continue to
characterize exoplanets at an unprecedented spectral resolution, thereby
growing its already successful track record of 23 detected exoplanets and brown
dwarfs from Phase I. Using the new vortex fiber nulling (VFN) mode, Phase II
will also be able to search for exoplanets at small angular separations less
than 45 milliarcseconds which conventional coronagraphs cannot reach.
