  In this paper, we will derive the cross section formula for the Higgs pair
production at a linear $e^+e^-$ collider in models with large extra dimensions
and study the feasibility of its measurement through realistic Monte Carlo
simulations. Since the process has essentially no Standard Model background,
once produced, it will provide us with a very clean signature of physics beyond
the Standard Model. Moreover, since the final state particles are spinless, the
spin 2 of the intermediate virtual KK gravitons has to be conserved by the
orbital angular momentum of the Higgs pair. This results in a very
characteristic angular distribution of the final states. Taking into account
finite detector acceptance and resolutions as well as initial state radiation
and beamstrahlung, we demonstrate in this paper that, given a sufficiently high
center of mass energy, the angular distribution of the Higgs pair is indeed
measurable at the linear collider and will allow us to prove the spin 2 nature
of the KK gravitons exchanged in the s-channel.
