Spontaneous Parametric Down-Conversion in Integrated Hybrid SixNy-PPLN Waveguides for High-Dimensional Qubit Entanglement

We review recent theoretical and experimental works where are proposed and demonstrated how to use photon pairs created by spontaneous parametric down-conversion to generate entangled states of D-dimensional quantum systems, or qudits. This is the first demonstration of high-dimensional entanglement based on the intrinsic transverse momentum entanglement of the type-II down-converted photons. The qudit space is defined by an aperture made up of an opaque screen with D slits (paths), placed in the arms of the twin photons. By manipulating the pump beam profile we can prepare different entangled states of these possible paths. We focus our attention on an important case for applications in quantum information: the maximally entangled states. Experimental results for qudits with D=4 and D=8 are shown and measuring a two-photon conditional interference, we also demonstrate the nonclassical character of the correlations.

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Generalized Bell inequalities with parametric down-conversion

Quantum Information and Computation ◽

10.26421/qic3.s-2 ◽

2003 ◽

Vol 3 (special) ◽

pp. 471-479

Author(s):

A. Lamas-Linares ◽

W.T.M. Irvine ◽

J.C. Howell ◽

D. Bouwmeester

Keyword(s):

Bell Inequalities ◽

Experimental Results ◽

High Dimensional ◽

Parametric Down Conversion ◽

Down Conversion ◽

Influence Of Noise

We analize the suitability of states generated by stimulated parametric down-conversion for the testing of high dimensional Bell-type inequalities. Two families of bipartite inequalities are considered. For both it is found that the states are good candidates for the tests and some experimental results for one spin-1 inequality are given. The influence of noise and the possibility of supurious results are discussed.

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Metalens-array–based high-dimensional and multiphoton quantum source

Science ◽

10.1126/science.aba9779 ◽

2020 ◽

Vol 368 (6498) ◽

pp. 1487-1490 ◽

Cited By ~ 4

Author(s):

Lin Li ◽

Zexuan Liu ◽

Xifeng Ren ◽

Shuming Wang ◽

Vin-Cent Su ◽

...

Keyword(s):

Nonlinear Crystal ◽

High Dimensional ◽

Two Photon ◽

Parametric Down Conversion ◽

State Generation ◽

Quantum Optical ◽

Photon Generation ◽

Down Conversion ◽

Photon Source ◽

Photon Path

The development of two-dimensional metasurfaces has shown great potential in quantum-optical technologies because of the excellent flexibility in light-field manipulation. By integrating a metalens array with a nonlinear crystal, we demonstrate a 100-path spontaneous parametric down-conversion photon-pair source in a 10 × 10 array, which shows promise for high-dimensional entanglement and multiphoton-state generation. We demonstrate two-, three- and four-dimensional two-photon path entanglement with different phases encoded by metalenses with fidelities of 98.4, 96.6, and 95.0%, respectively. Furthermore, four-photon and six-photon generation is observed with high indistinguishability of photons generated from different metalenses. Our metalens-array–based quantum photon source is compact, stable, and controllable, indicating a new platform for integrated quantum devices.

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Creating high-dimensional time-bin entanglement using mode-locked lasers

Quantum Information and Computation ◽

10.26421/qic2.6-1 ◽

2002 ◽

Vol 2 (6) ◽

pp. 425-433

Author(s):

H. de Riedmatten ◽

I. Marcikic ◽

H. Zbinden ◽

N. Gisin

Keyword(s):

High Dimensional ◽

Photon State ◽

Two Photon ◽

Length Difference ◽

Fabry Perot ◽

Parametric Down Conversion ◽

Path Length Difference ◽

Mode Locked Lasers ◽

Down Conversion ◽

Feasible Experiment

We present a new scheme to generate high dimensional entanglement between two photonic systems. The idea is based on parametric down conversion with a sequence of pump pulses generated by a mode-locked laser. We prove experimentally the feasibility of this scheme by performing a Franson-type Bell test using a 2-way interferometer with path-length difference equal to the distance between 2 pump pulses. With this experiment, we can demonstrate entanglement for a two-photon state of at least dimension D=11. Finally, we propose a feasible experiment to show a Fabry-Perot like effect for a high dimensional two-photon state.

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