  We present the results of a linear optics photonic implementation of a
quantum circuit that simulates a phase covariant cloner, by using two different
degrees of freedom of a single photon. We experimentally simulate the action of
two mirrored $1\rightarrow 2$ cloners, each of them biasing the cloned states
into opposite regions of the Bloch sphere. We show that by applying a random
sequence of these two cloners, an eavesdropper can mitigate the amount of noise
added to the original input state and therefore prepare clones with no bias but
with the same individual fidelity, masking its presence in a quantum key
distribution protocol. Input polarization qubit states are cloned into path
qubit states of the same photon, which is identified as a potential
eavesdropper in a quantum key distribution protocol. The device has the
flexibility to produce mirrored versions that optimally clone states on either
the northern or southern hemispheres of the Bloch sphere, as well as to
simulate optimal and non-optimal cloning machines by tuning the asymmetry on
each of the cloning machines.
