  We present a scheme of quantum repeater that uses entangled multimode
coherent states which are obtained by electro-optic modulation of symmetric and
antisymmetric Schr\"odinger cat states. In this method subcarrier modes of the
phase modulated states generated by the remote parties are sent to a symmetric
beam splitter at the central node. The entangled coherent states are heraldedly
prepared by photon counting measurements at the output channels of the beam
splitter. We study how the effects of decoherence in the quantum channel affect
statistics of photocounts and corresponding fidelity. We show how the proposed
scheme can be useful for extending range of quantum key distribution with sub
carrier wave encoding by exploiting quantum teleportation with the generated
entanglement.
