  One of the important function in optical communication system is the
distribution of information encoded in an optical beam. It is not a problem to
accomplish this in a classical system since classical information can be copied
at will. However, challenges arise in quantum system because extra quantum
noise is often added when the information content of a quantum state is
distributed to various users. Here, we experimentally demonstrate a quantum
information tap by using a fiber optical parametric amplifier (FOPA) with
correlated inputs, whose noise is reduced by the destructive quantum
interference through quantum entanglement between the signal and the idler
input fields. By measuring the noise figure of the FOPA and comparing with a
regular FOPA, we observe an improvement of 0.7+-0.1 dB and 0.84+-0.09 dB from
the signal and idler outputs, respectively. When the low noise FOPA functions
as an information splitter, the device has a total information transfer
coefficient of Ts+Ti=1.47+-0.2, which is greater than the classical limit of 1.
Moreover, this fiber based device works at the 1550 nm telecom band, so it is
compatible with the current fiber-optical network.
