title: Experimental generation of 6 dB continuous variable entanglement from a nondegenerate optical parametric amplifier.
abstract: 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.
authors.affiliation: State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan, 030006, People's Republic of China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Heng
authors.initials: H
authors.lastname: Shen
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Jin
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Su
authors.forename: Changde
authors.initials: C
authors.lastname: Xie
authors.forename: Kunchi
authors.initials: K
authors.lastname: Peng
mesh_terms: D000669:Amplifiers, Electronic; D004867:Equipment Design; D019544:Equipment Failure Analysis; D055096:Optical Devices