Effects of mode coupling on the generation of quadrature Einstein-Podolsky-Rosen entanglement in a type-II optical parametric oscillator below threshold

Laurat, Julien; Coudreau, Thomas; Keller, G.; Treps, Nicolas; Fabre, Claude

doi:10.1103/physreva.71.022313

Cited by 63 publications

(47 citation statements)

References 22 publications

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“…We emphasize that twomode squeezed states with squeezing parameters of the order of unity are well within experimental reach, as demonstrated, for example, in Ref. [27].…”

Section: Non-classical Correlationsmentioning

confidence: 74%

Distributing fully optomechanical quantum correlations

Mazzola

Paternostro

2011

Phys. Rev. A

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We present a scheme to prepare quantum correlated states of two mechanical systems based on the pouring of pre-available all-optical entanglement into the state of two micro-mirrors belonging to remote and noninteracting optomechanical cavities. We show that, under realistic experimental conditions, the protocol allows for the preparation of a genuine quantum state of a composite mesoscopic system whose non-classical features extend beyond the occurrence of entanglement. We finally discuss a way to access such mechanical correlations.

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“…We emphasize that twomode squeezed states with squeezing parameters of the order of unity are well within experimental reach, as demonstrated, for example, in Ref. [27].…”

Section: Non-classical Correlationsmentioning

confidence: 74%

Distributing fully optomechanical quantum correlations

Mazzola

Paternostro

2011

Phys. Rev. A

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“…Given the fact that we used just a single squeezed mode, our result is quite remarkable. To the best of our knowledge only one work reported a stronger EPR entanglement [8], however, based on type II parametric down conversion and therefore to an equivalent of two squeezed input modes.…”

Section: Demonstration Of Epr Entanglementmentioning

confidence: 99%

Strong Einstein-Podolsky-Rosen entanglement from a single squeezed light source

et al. 2011

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Einstein-Podolsky-Rosen (EPR) entanglement is a criterion that is more demanding than just certifying entanglement. We theoretically and experimentally analyze the low resource generation of bi-partite continuous variable entanglement, as realized by mixing a squeezed mode with a vacuum mode at a balanced beam splitter, i.e. the generation of so-called vacuum-class entanglement. We find that in order to observe EPR entanglement the total optical loss must be smaller than 33.3 %. However, arbitrary strong EPR entanglement is generally possible with this scheme. We realize continuous wave squeezed light at 1550 nm with up to 9.9 dB of non-classical noise reduction, which is the highest value at a telecom wavelength so far. Using two phase controlled balanced homodyne detectors we observe an EPR co-variance product of 0.502 ± 0.006 < 1, where 1 is the critical value. We discuss the feasibility of strong Gaussian entanglement and its application for quantum key distribution in a short-distance fiber network.

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“…Twenty years ago, Kimble's group experimentally generated a pair of CV entangled optical beams with a NOPA and demon- * jiaxj@sxu.edu.cn strated the EPR paradox firstly in CV regime [13]. Then, NOPAs operating at different version (above or lower the threshold, amplification or de-amplification) are used as the sources of generating optical CV entangled states and the produced EPR beams are applied in a variety of CV QIP experiments [14][15][16][17][18][19]. However, in a long period the EPR entanglement level was kept around −4 dB or lower [13][14][15][16][17][18][19].…”

mentioning

confidence: 99%

“…Then, NOPAs operating at different version (above or lower the threshold, amplification or de-amplification) are used as the sources of generating optical CV entangled states and the produced EPR beams are applied in a variety of CV QIP experiments [14][15][16][17][18][19]. However, in a long period the EPR entanglement level was kept around −4 dB or lower [13][14][15][16][17][18][19]. Until 2010, after a series of strictly technical improvement on the NOPA system, the EPR entanglement degree was raised to −6 dB [20], which is the best reported result on NOPA system.…”

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confidence: 99%

Cascaded entanglement enhancement

Yan

Jia

et al. 2012

Phys. Rev. A

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We present a cascaded system consisting of three non-degenerate optical parametric amplifiers (NOPAs) for the generation and the enhancement of quantum entanglement of continuous variables. The entanglement of optical fields produced by the first NOPA is successively enhanced by the second and the third NOPAs from −5.3 dB to −8.1 dB below the quantum noise limit. The dependence of the enhanced entanglement on the physical parameters of the NOPAs and the reachable entanglement limitation for a given cascaded NOPA system are calculated. The calculation results are in good agreement with the experimental measurements.PACS numbers: 03.67. Bg, 42.50.Dv, 03.65.Ud, 42.50.Lc Nonlocal quantum entanglement is the key resource to realize quantum information processing (QIP) [1][2][3]. The entangled states of single photons (qubits) and optical modes (qumodes) have been applied in QIP with discrete and continuous variable (DV and CV) regimes, respectively [4,5]. The quadrature squeezed states of light are the essential resource states in CV QIP since squeezing is the necessary base to establish quantum entanglement among optical fields [6]. A scheme of generating CV optical entangled states is to interfere two single-mode squeezed states of light with an identical frequency and a constant phase-difference on a 50/50 beamsplitter [5,7]. The two single-mode squeezed states are often produced by a pair of degenerate optical parametric amplifiers (DOPAs) with identical type-I nonlinear crystal pumped by a laser to ensure high interference efficiency. Through carefully technical improvement on suppressing the phase fluctuation of optical field and reducing the intra-cavity losses of DOPA, the squeezing level of the single-mode squeezed states is continually renewed in recent years [8][9][10]. So far, the squeezing over −12 dB below the quantum noise limitation (QNL) has been achieved by a group in Hannover [9,10]. Coupling a single-mode squeezed state of −9.9 dB and a vacuum field on a 50/50 beam splitter, the Einstein-Podolsky-Rosen (EPR) entangled state of light (also named two-mode squeezed state) with the quantum correlation of amplitude and phase quadratures of −3 dB below the QNL was obtained in 2011 [11]. The four-mode CV entanglement of −6 dB below the QNL was achieved by combing four initial single-mode squeezed states generated by four DOPAs [12]. The highest CV entanglement produced by coupling single-mode squeezed states is −6 dB below the QNL up to now [12].Another important device to generate CV EPR entangled state of optical field is the non-degenerate optical parametric amplifier (NOPA) consisting an optical cavity and a type-II nonlinear crystal. Through the intra-cavity frequency-down conversion process in a NOPA, a pair of non-degenerate optical modes with amplitude and phase quadrature correlations is directly produced, which is an EPR entangled state [13]. Twenty years ago, Kimble's group experimentally generated a pair of CV entangled optical beams with a NOPA and demon- * jiaxj@sxu.edu.cn strated the EP...

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Effects of mode coupling on the generation of quadrature Einstein-Podolsky-Rosen entanglement in a type-II optical parametric oscillator below threshold

Cited by 63 publications

References 22 publications

Distributing fully optomechanical quantum correlations

Distributing fully optomechanical quantum correlations

Strong Einstein-Podolsky-Rosen entanglement from a single squeezed light source

Cascaded entanglement enhancement

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