Marc Jofre

Publications (5)8.74 Total impact

• Article: Phase-stable source of polarization-entangled photons in a linear double-pass configuration.

  Fabian Steinlechner, Sven Ramelow, Marc Jofre, Marta Gilaberte, Thomas Jennewein, Juan P Torres, Morgan W Mitchell, Valerio Pruneri
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  ABSTRACT: 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%.
  Optics Express 05/2013; 21(10):11943-51. · 3.59 Impact Factor
• Article: A high-brightness source of polarization-entangled photons optimized for applications in free space.

  Fabian Steinlechner, Pavel Trojek, Marc Jofre, Henning Weier, Daniel Perez, Thomas Jennewein, Rupert Ursin, John Rarity, Morgan W Mitchell, Juan P Torres, Harald Weinfurter, Valerio Pruneri
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  ABSTRACT: 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.
  Optics Express 04/2012; 20(9):9640-9. · 3.59 Impact Factor
• Source

  Available from: ArXiv

  Article: A passive transmitter for quantum key distribution with coherent light

  Marcos Curty, Marc Jofre, Valerio Pruneri, Morgan W. Mitchell
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  ABSTRACT: Signal state preparation in quantum key distribution schemes can be realized using either an active or a passive source. Passive sources might be valuable in some scenarios; for instance, in those experimental setups operating at high transmission rates, since no externally driven element is required. Typical passive transmitters involve parametric down-conversion. More recently, it has been shown that phase-randomized coherent pulses also allow passive generation of decoy states and Bennett-Brassard 1984 (BB84) polarization signals, though the combination of both setups in a single passive source is cumbersome. In this paper, we present a complete passive transmitter that prepares decoy-state BB84 signals using coherent light. Our method employs sum-frequency generation together with linear optical components and classical photodetectors. In the asymptotic limit of an infinite long experiment, the resulting secret key rate (per pulse) is comparable to the one delivered by an active decoy-state BB84 setup with an infinite number of decoy settings.
  08/2011;
• Article: Active and Passive Optical Sources for QKD

  Marc Jofre, Fabian Steinlechner, Gabriele Anzolin, Waldimar Amaya, Jose Capmany, Rupert Ursin, Jose Luis Vilas, Eusebio Bernabeu, Juan Pérez Torres, Morgan Mitchell, Valerio Pruneri
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  ABSTRACT: We report on optical sources for high bit rate Quantum Key Distribution (QKD) over free-space links. Semiconductor optical amplifiers have been used for the first time to our knowledge and allowing 100Mb/s with improved security.
  05/2011;
• Source

  Available from: arxiv.org

  Article: Polarization change induced by a galvanometric optical scanner.

  Gabriele Anzolin, Arnaud Gardelein, Marc Jofre, Gabriel Molina-Terriza, Morgan W Mitchell
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  ABSTRACT: We study the optical properties of a two-axis galvanometric optical scanner constituted by a pair of rotating planar mirrors, focusing our attention on the transformation induced on the polarization state of the input beam. We obtain the matrix that defines the transformation of the propagation direction of the beam and the Jones matrix that defines the transformation of the polarization state. Both matrices are expressed in terms of the rotation angles of two mirrors. Finally, we calculate the parameters of the general rotation in the Poincaré sphere that describes the change in the polarization state for each mutual orientation of the mirrors.
  Journal of the Optical Society of America A 09/2010; 27(9):1946-52. · 1.56 Impact Factor