We experimentally demonstrate that the quantum entanglement between amplitude and phase quadratures of optical modes produced from a non-degenerate optical parametric amplifier (NOPA) can be enhanced and manipulated phase-sensitively by means of another NOPA. When both NOPAs operate at de-amplification, the entanglement degree is increased at the cavity resonance of the second NOPA. When the first NOPA operates at de-amplification and the second one at amplification, the spectral features of the correlation variances are significantly changed. The experimental results are in good agreement with the theoretical expectation.
@article{arxiv.1003.1357,
title = {Continuous variable entanglement enhancement and manipulation by a sub-threshold type-II optical parametric amplifier},
author = {Yana Shang and Xiaojun Jia and Yumei Shen and Changde Xie and Kunchi Peng},
journal= {arXiv preprint arXiv:1003.1357},
year = {2010}
}