  We compute the spectrum of primordial gravitational wave perturbations in
open de Sitter spacetime. The background spacetime is taken to be the
continuation of an O(5) symmetric instanton saddle point of the Euclidean no
boundary path integral. The two-point tensor fluctuations are computed directly
from the Euclidean path integral. The Euclidean correlator is then analytically
continued into the Lorentzian region where it describes the quantum mechanical
vacuum fluctuations of the graviton field. Unlike the results of earlier work,
the correlator is shown to be unique and well behaved in the infrared. We show
that the infrared divergence found in previous calculations is due to the
contribution of a discrete gauge mode inadvertently included in the spectrum.
