Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:0804.3799 · Applied Physics Letters

Collinear source of polarization-entangled photon pairs at nondegenerate wavelengths

Pavel Trojek, Harald Weinfurter

Published May 26, 2008• 73 citations
arXivHTMLPDF

Abstract

We report on a simple but highly efficient source of polarization-entangled photon pairs at nondegenerate wavelengths. The fully collinear configuration of the source enables very high coupling efficiency into a single optical mode and allows the use of long nonlinear crystals. With optimized dispersion compensation, it is possible to use a free-running laser diode as pump source and to reach an entanglement fidelity of 99.4% at rates as high as 27000pairs∕s∕mW of pump power.

DOI
10.1063/1.2924280

Related papers

A high-brightness source of polarization-entangled photons optimized for applications in free space

Steinlechner, F., Trojek, P., Jofre, M. +9 more

We present a simple but highly efficient source of polarization-entangled photons based on spontaneous parametric down-conversion (SPDC) in bulk periodically poled potassium titanyl phosphate crystals (PPKTP) pumped by a 405 nm laser diode. Utilizing one of the highest available nonlinear coefficients in a non-degenerate, collinear type-0 phase-matching configuration, we generate polarization entanglement via the crossed-crystal scheme and detect 0.64 million photon pair events/s/mW, while maintaining an overlap fidelity with the ideal Bell state of 0.98 at a pump power of 0.025 mW.

•Apr 23, 2012•56 citations

A high-brightness source of polarization-entangled photons optimized for applications in free space

Fabian Steinlechner, Pavel Trojek, Marc Jofre +9 more

We present a simple but highly efficient source of polarization-entangled photons based on spontaneous parametric down-conversion (SPDC) in bulk periodically poled potassium titanyl phosphate crystals (PPKTP) pumped by a 405 nm laser diode. Utilizing one of the highest available nonlinear coefficients in a non-degenerate, collinear type-0 phase-matching configuration, we generate polarization entanglement via the crossed-crystal scheme and detect 0.64 million photon pair events/s/mW, while maintaining an overlap fidelity with the ideal Bell state of 0.98 at a pump power of 0.025 mW.

arXiv:1204.5330•Optics Express•Apr 12, 2012•108 citations

Compact source of polarization-entangled photon pairs

Pavel Trojek, Mohamed Bourennane, Christian Kurtsiefer +1 more

A compact source of polarization-entangled photon pairs is developed using a blue single-mode laser diode (/spl lambda/ = 402 nm, P = 30 mW) as the pump source of a beta-barium-borate (BBO) nonlinear optical crystal . Using the technique to optimize the collection efficiency, the created photon pairs are coupled into single-mode optical fibers, which are directly connected to quenched silicon avalanche photodiodes (Si APDs). The entanglement of the generated photon pairs was tested with the measurement of the polarization correlations in H/V and +45/spl deg// -45/spl deg/ basis and by violating the Clauser-Horne-Shimony-Holt (CHSH)-type Bell inequality. This compact, robust and economic source can be employed in any application of quantum information and quantum communication, in particular in practicable entanglement based quantum key distribution.

European Quantum Electronics Conference (EQEC)•Jan 1, 2003•2 citations

Phase-stable source of polarization-entangled photons in a linear double-pass configuration

Steinlechner, F., Sven Ramelow, Jofre, Martí +5 more

We demonstrate a compact, robust, and highly efficient source of polarization-entangled photons, based on linear bi-directional down-conversion in a novel ‘folded sandwich’ configuration. Bi-directionally pumping a single periodically poled KTiOPO4 (ppKTP) crystal with a 405-nm laser diode, we generate entangled photon pairs at the non-degenerate wavelengths 784 nm (signal) and 839 nm (idler), and achieve an unprecedented detection rate of 11.8 kcps for 10.4 μW of pump power (1.1 million pairs / mW), in a 2.9-nm bandwidth, while maintaining a very high two-photon entanglement quality, with a Bell-state fidelity of 99.3 ± 0.3%.

•Jan 1, 2013•24 citations

Phase-stable source of polarization-entangled photons in a linear double-pass configuration

Fabian Steinlechner, Sven Ramelow, Marc Jofre +5 more

We demonstrate a compact, robust, and highly efficient source of polarization-entangled photons, based on linear bi-directional down-conversion in a novel 'folded sandwich' configuration. Bi-directionally pumping a single periodically poled KTiOPO(4) (ppKTP) crystal with a 405-nm laser diode, we generate entangled photon pairs at the non-degenerate wavelengths 784 nm (signal) and 839 nm (idler), and achieve an unprecedented detection rate of 11.8 kcps for 10.4 μW of pump power (1.1 million pairs / mW), in a 2.9-nm bandwidth, while maintaining a very high two-photon entanglement quality, with a Bell-state fidelity of 99.3 ± 0.3%.

arXiv:1305.1519•Optics Express•May 8, 2013•44 citations

Polarization Entangled Photon-pair Source Using a Broadband Pump

Chithrahanu Perumangatt, Alexander Lohrmann, Aitor Villar +1 more

We experimentally demonstrate a high quality, 100 nm broadband polarization entangled photon-pair source using a linear interferometer design based on a single periodically-poled potassium titanyl phosphate (PPKTP) crystal pumped with a free running laser diode.

Conference on Lasers and Electro-Optics•Jan 1, 2020•0 citations
We report on a simple but highly efficient source of polarization-entangled photon pairs at nondegenerate wavelengths. The fully collinear configuration of the source enables very high coupling efficiency into a single optical mode and allows the use of long nonlinear crystals. With optimized dispersion compensation, it is possible to use a free-running laser diode as pump source and to reach an entanglement fidelity of 99.4% at rates as high as 27000pairs∕s∕mW of pump power.
We present a simple but highly efficient source of polarization-entangled photons based on spontaneous parametric down-conversion (SPDC) in bulk periodically poled potassium titanyl phosphate crystals (PPKTP) pumped by a 405 nm laser diode. Utilizing one of the highest available nonlinear coefficients in a non-degenerate, collinear type-0 phase-matching configuration, we generate polarization entanglement via the crossed-crystal scheme and detect 0.64 million photon pair events/s/mW, while maintaining an overlap fidelity with the ideal Bell state of 0.98 at a pump power of 0.025 mW.
We present a simple but highly efficient source of polarization-entangled photons based on spontaneous parametric down-conversion (SPDC) in bulk periodically poled potassium titanyl phosphate crystals (PPKTP) pumped by a 405 nm laser diode. Utilizing one of the highest available nonlinear coefficients in a non-degenerate, collinear type-0 phase-matching configuration, we generate polarization entanglement via the crossed-crystal scheme and detect 0.64 million photon pair events/s/mW, while maintaining an overlap fidelity with the ideal Bell state of 0.98 at a pump power of 0.025 mW.
A compact source of polarization-entangled photon pairs is developed using a blue single-mode laser diode (/spl lambda/ = 402 nm, P = 30 mW) as the pump source of a beta-barium-borate (BBO) nonlinear optical crystal . Using the technique to optimize the collection efficiency, the created photon pairs are coupled into single-mode optical fibers, which are directly connected to quenched silicon avalanche photodiodes (Si APDs). The entanglement of the generated photon pairs was tested with the measurement of the polarization correlations in H/V and +45/spl deg// -45/spl deg/ basis and by violating the Clauser-Horne-Shimony-Holt (CHSH)-type Bell inequality. This compact, robust and economic source can be employed in any application of quantum information and quantum communication, in particular in practicable entanglement based quantum key distribution.
We demonstrate a compact, robust, and highly efficient source of polarization-entangled photons, based on linear bi-directional down-conversion in a novel ‘folded sandwich’ configuration. Bi-directionally pumping a single periodically poled KTiOPO4 (ppKTP) crystal with a 405-nm laser diode, we generate entangled photon pairs at the non-degenerate wavelengths 784 nm (signal) and 839 nm (idler), and achieve an unprecedented detection rate of 11.8 kcps for 10.4 μW of pump power (1.1 million pairs / mW), in a 2.9-nm bandwidth, while maintaining a very high two-photon entanglement quality, with a Bell-state fidelity of 99.3 ± 0.3%.
We demonstrate a compact, robust, and highly efficient source of polarization-entangled photons, based on linear bi-directional down-conversion in a novel 'folded sandwich' configuration. Bi-directionally pumping a single periodically poled KTiOPO(4) (ppKTP) crystal with a 405-nm laser diode, we generate entangled photon pairs at the non-degenerate wavelengths 784 nm (signal) and 839 nm (idler), and achieve an unprecedented detection rate of 11.8 kcps for 10.4 μW of pump power (1.1 million pairs / mW), in a 2.9-nm bandwidth, while maintaining a very high two-photon entanglement quality, with a Bell-state fidelity of 99.3 ± 0.3%.