  We experimentally demonstrate the underlying physical mechanism of the
recently proposed protocol for superreplication of quantum phase gates [W.
D\"ur, P. Sekatski, and M. Skotiniotis, Phys. Rev. Lett. 114, 120503 (2015)],
which allows to produce up to $N^2$ high-fidelity replicas from N input copies
in the limit of large N. Our implementation of 1->2 replication of the
single-qubit phase gates is based on linear optics and qubits encoded into
states of single photons. We employ the quantum Toffoli gate to imprint
information about the structure of an input two-qubit state onto an auxiliary
qubit, apply the replicated operation to the auxiliary qubit, and then
disentangle the auxiliary qubit from the other qubits by a suitable quantum
measurement. We characterize the replication protocol by full quantum process
tomography and observe good agreement of the experimental results with theory.
