We demonstrate optical spin polarization of the neutrally-charged silicon-vacancy defect in diamond ($mathrm{SiV^{0}}$), an $S=1$ defect which emits with a zero-phonon line at 946 nm. The spin polarization is found to be most efficient under resonant excitation, but non-zero at below-resonant energies. We measure an ensemble spin coherence time $T_2>100~mathrm{mu s}$ at low-temperature, and a spin relaxation limit of $T_1>25~mathrm{s}$. Optical spin state initialization around 946 nm allows independent initialization of $mathrm{SiV^{0}}$ and $mathrm{NV^{-}}$ within the same optically-addressed volume, and $mathrm{SiV^{0}}$ emits within the telecoms downconversion band to 1550 nm: when combined with its high Debye-Waller factor, our initial results suggest that $mathrm{SiV^{0}}$ is a promising candidate for a long-range quantum communication technology.
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