  The negatively-charged silicon-vacancy ($\mathrm{SiV}^{-}$) center in diamond
is a bright source of indistinguishable single photons and a useful resource in
quantum information protocols. Until now, $\mathrm{SiV}^{-}$ centers with
narrow optical linewidths and small inhomogeneous distributions of
$\mathrm{SiV}^{-}$ transition frequencies have only been reported in samples
doped with silicon during diamond growth. We present a technique for producing
implanted $\mathrm{SiV}^{-}$ centers with nearly lifetime-limited optical
linewidths and a small inhomogeneous distribution. These properties persist
after nanofabrication, paving the way for incorporation of high-quality
$\mathrm{SiV}^{-}$ centers into nanophotonic devices.
