  We report the first experimental realization of an ''optimal'' quantum device
able to perform a Minimal Disturbance Measurement (MDM) on polarization encoded
qubits saturating the theoretical boundary established between the classical
knowledge acquired of any input state, i.e. the classical "guess", and the
fidelity of the same state after disturbance due to measurement . The device
has been physically realized by means of a linear optical qubit manipulation,
post-selection measurement and a classical feed-forward process.
