  A general quantum channel consisting of a decohering and a filtering element
carries one qubit of an entangled photon pair. As we apply a local filter to
the other qubit, some mutual quantum information between the two qubits is
restored depending on the properties of the noise mixed into the signal. We
demonstrate a drastic difference between channels with bit-flip and phase-flip
noise and further suggest a scheme for maximal recovery of the quantum
information.
