Two-Mode Nonlinear Quantum Optics System: A Non-degenerate Parametric Quantum Optical Amplifier

Yu Wang, Heng Shen, Xiaoli Jin +3 more

We experimentally demonstrated that the quantum correlations of amplitude and phase quadratures between signal and idler beams produced from a non-degenerate optical parametric amplifier (NOPA) can be significantly improved by using a mode cleaner in the pump field and reducing the phase fluctuations in phase locking systems. Based on the two technical improvements the quantum entanglement measured with a two-mode homodyne detector is enhanced from approximately 4 dB to approximately 6 dB below the quantum noise limit using the same NOPA and nonlinear crystal.

Xuesong Gao

R. Usefi, Mohammad Kazem Tavassoly

Our purpose in this paper is to investigate the response of a well-known nonlinear quantum optical medium, i.e. non-degenerate parametric amplifier (NDPA), to the pair coherent and two-mode squeezed states, distinctly, both analytically and numerically. To achieve the aim, we start from the NDPA quantum Hamiltonian in the rotating wave approximation (RWA) and via solving the Heisenberg equations of motion of signal and idler modes of the dynamical system is derived, by which we can achieve the time evolution of the NDPA response to the above-mentioned input field states. Accordingly, we are able to evaluate two important nonclassical properties, i.e. photonic entanglement and photon statistics (second-order correlation function and antibunching effect) after the interaction with NDPA for the output emitted fields, and compare the results with the associated quantities for the input field states. Summing up, our numerical simulations show that the amplification (and in some cases the appearance) of the considered nonclassical properties of the radiation field in the output states is clearly confirmed. The results can be beneficial for various quantum science and technology protocols, i.e. quantum communication, quantum metrology, quantum teleportation and quantum computing.

Kazuro Kikuchi

We analyze the noise characteristics of an optical transmission system repeated by two-mode phase-sensitive optical parametric amplifiers. In such a system, the non-degenerated signal and idler waves co-propagate through the link, interacting with each other in the optical parametric amplifiers. For the first time, we derive a closed-form expression for the accumulated noise using the quantum-mechanical Langevin-equation approach. The derived noise formula allows calculating the noise figure of the optical-amplifier chain under the influence of the internal loss of the amplifiers and the transmission loss of the link, thereby theoretically demonstrating its low-noise characteristics.

Eiichi Hanamura, Yutaka Kawabe, Akio Yamanaka