Quantum optical cloning amplifier

Abstract

We demonstrate experimentally that a type-II pulsed optical parametric amplifier can duplicate (or, clone) a signal in the quadrature it amplifies. Although this device is an amplifier with large gain, it meets the quantitative criteria for quantum nondemolition measurements and, thus, operates in the nonclassical regime. It can be used as a noiseless amplifying optical tap which, at the same time, can overcome the noise introduced downstream by propagation and detection losses.