Broadband multi-channel quantum noise suppression and phase-sensitive modulation based on entangled beam

Abstract

We present a theoretical scheme for broadband multi-channel quantum noise suppression and phase-sensitive modulation of continuous variables in a coupled resonant system with quantum entanglement properties. The effects of different coupling strengths and pumping power in suppressing quantum noise and controlling the width of quantum interference channels are analyzed carefully. Furthermore, quantum noise suppression at quadrature amplitude is obtained with phase-sensitive modulation. It shows that the entanglement strength of the output field and the quantum noise suppression effect can be enhanced significantly by a strong pumping filed due to the interaction of the pumping light with the nonlinear crystal. The full width at half maxima (FWHM) of the noise curve at the resonant peak (Δ = 0 MHz) is broadened 2.17 times compared to the single cavity. In the strong coupling resonant system, the FWHM at Δ = 0 MHz (Δ = ±3.1 MHz) is also broadened 1.27 (3.53) times compared to the weak coupling resonant system case. The multi-channel quantum interference creates an electromagnetically-induced-transparent-like line shape (EIT-like), which can be used to improve the transmission efficiency and stability of wave packets in quantum information processing and quantum memory.