Fully guided-wave photon pair source for quantum applications

Vergyris, Panagiotis; Kaiser, Florian; Gouzien, Élie; Sauder, Grégory; Lunghi, Tommaso; Tanzilli, Sébastien

doi:10.1088/2058-9565/aa6ed2

Cited by 43 publications

(63 citation statements)

References 55 publications

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“…The length error of PMFs has to be sufficiently small. Experimentally, the length error can be controlled to <1cm [24], which are sufficient for maintaining coherence(see supplementary material). The hyperentanglement can thus maintain high entanglement in each DOF at the output.…”

Section: The Deterministic Separation Of Two Photons By Interference mentioning

confidence: 99%

“…The accessible dimensionality of the biphoton states in collinear case is only 4×N , in contrast to 8×N when the biphotons are in two different spatial modes(see supplementary material). To see the limitations of such state, consider the simplest case when N = 1:If we separate the biphotons into two spatial modes by frequency, then frequency entanglement is destroyed, resulting in [22,24]:If, on the other hand, we separate the biphotons by polarization, the polarization entanglement is destroyed [22]:|ψ N =1,f rq = 1 √ 2 (|ω s 1 |ω i 2 + |ω i 1 |ω s 2 ) ⊗ |H 1 |V 2…”

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confidence: 99%

“…If we separate the biphotons into two spatial modes by frequency, then frequency entanglement is destroyed, resulting in [22,24]:…”

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Recovering the full dimensionality of hyperentanglement in collinear photon pairs

et al. 2020

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Exploiting hyperentanglement of photon pairs, that is, simultaneous entanglement in multiple degrees of freedom(DOFs), increases the dimensionality of Hilbert spaces for quantum information processing. However, generation of hyperentangled photon pairs collinearlly, while produces high brightness, results in a smaller Hilbert space due to the two photons being in the same spatial mode. In this letter, we point out that one can recover the full dimensionality of such hyperentanglement through a simple interference set up, similar to the time-reversed Hong-Ou-Mandel (TR-HOM) process. Different from the standard TR-HOM, we point out a critical phase condition has to be satisfied in order to recover the hyperentanglement. We theoretically analyze the realization of this approach and discuss the feasibility of generating truly hyperentangled photon pairs. Our proposed approach does not require post-selection and hence enables efficient hyper-entangled photon pairs generation for high-dimensional quantum applications.Entangled photons play a critical role in many applications of quantum opticshorodecki2009quantum. Photons that are simultaneously entangled in more than one degree of freedom(DOF), the so-called 'hyperentangled' states, have attracted much recent interest [1][2][3]. Hyperentanglement expands the dimensionality of the Hilbert space of biphotons, enables complete Bell state analysis [4,5], increases the information capacity per pair photons [6,7] and therefore lays the fundation of superdense-coding quantum communication [8][9][10]. It has also become the key technology for certain tests of fundamental physics [11,12].The generation of entangled photons is most conveniently done in a nonlinear medium. When the phase matching can be satisfied over a bandwidth much greater than the pump bandwidth, the photons are frequency entangled as a result of energy conservation. Entanglement in another DOF can be arranged through various means, such as type II phase matching for polarizationentanglement[13], delayed interferometer for time-bin entanglement [14], or simultaneous phase matching for various orbital angular momentum modes [15]. Here, we consider hyper-entanglement in frequency and polarization DOFs, as frequency and polarization of photons are robust over large transmission distances in optical fibre. Entanglement in these two DOFs can also be generated relatively straightforwardly in fibre [16] and nonlinear waveguides [17]. While collinear photon pair generation in a fibre or a nonlinear waveguide is most efficient due to large nonlinear interaction length and no spatial filtering required (as opposed to non-collinear generation [18]), we will show that that collinear entangled photon pairs have a reduced dimensionality in Hilbert space.By "hyperentanglement", we mean not only the photons are entangled in both DOFs, but also that they are accessible individually, e.g. the hyperentangled photons are spatially separated. In collinear parametric processes such as type-II spontaneous parametric downconversion...

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Section: The Deterministic Separation Of Two Photons By Interference mentioning

confidence: 99%

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Recovering the full dimensionality of hyperentanglement in collinear photon pairs

et al. 2020

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“…In contrast to bulk sources, integrated sources provide high brightness due to strong confinement in waveguides and long interaction lengths, and can be designed to be spatially and spectrally singlemode, enabling simultaneously high fiber-coupling efficiency, spectral purity, and brightness. Many examples exist of high-brightness integrated sources, for example based on PDC in waveguides [19][20][21], or four-wave mixing in optical fibers [22,23] and silicon waveguides [24][25][26][27]. However, these sources have not yet demonstrated simultaneous high performance in all other parameters comparable to their bulk-optical counterparts.…”

Section: Introductionmentioning

confidence: 99%

“…In waveguides, this spectral-spatial coupling is eliminated thanks to the single-spatial-mode propagation, allowing the spectral purity to be independently optimized.Yet to date the most advanced experiments do not use waveguide sources, which can be understood in light of the difficulty in optimizing performance in integrated optics (see Table 2 in the appendix for comparison). The brightness of integrated sources is orders of magnitude larger than possible in bulk, reaching above 10 8 pairs/(s·mW) [21,23]. Entanglement fidelity over 95 %…”

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High-performance source of spectrally pure, polarization entangled photon pairs based on hybrid integrated-bulk optics

Meyer-Scott¹,

Prasannan²,

Eigner³

et al. 2018

Opt. Express

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Entangled photon pair sources based on bulk optics are approaching optimal design and implementation, with high state fidelities, spectral purities and heralding efficiencies, but generally low brightness. Integrated entanglement sources, while providing higher brightness and low-power operation, often sacrifice performance in output state quality and coupling efficiency. Here we present a polarization-entangled pair source based on a hybrid approach of waveguiding and bulk optics, addressing every metric simultaneously. We show 96 % fidelity to the singlet state, 82 % Hong-Ou-Mandel interference visibility, 43 % average Klyshko efficiency, and a high brightness of 2.9 × 10 6 pairs/(mode·s·mW), while requiring only microwatts of pump power.Our source combines for the first time high performance in all parameters simultaneously. Integrated single-mode photon pair sourcesOver the last two decades, efforts in improving entangled photon-pair sources based on bulk crystals and bulk optics have resulted in impressive performance in many measures (see Table 1 in the appendix for comparison). Entanglement fidelities above 99 % are readily achieved [1,2,17,30], and even above 99.9 % is possible [4]. Klyshko (heralding) efficiency [31], defined as the ratio of coincidence to singles counts, can reach 75 % [1,2,30,32,33]. The spectral purity, required to interfere photons from separate sources for multi-photon experiments, has been shown above 99 % [34].Unfortunately, bulk sources suffer from an intrinsic tradeoff between the brightness, or emitted photon rate per pump power (taken in the source before losses, but considering only modes which will reach the detectors), and the Klyshko efficiency [11]; for example setting the pump focus to enable coupling photon pairs to single mode fiber with 95 % efficiency necessarily reduces the brightness by a factor of ten from the maximum [35]. This tradeoff arises due to conflicting requirements on the focusing conditions: high brightness requires a tight pump focus which concentrates the down-converted light into the spatial modes collected by the fibers [36]. High Klyshko efficiency, however, requires a weak focus which more strongly correlates the spatial modes of signal and idler photons such that if one photon is coupled into fiber, the other is likely to be coupled too [37]. This tradeoff means the fundamental performance limits of bulk sources have largely been saturated. Furthermore, sources at telecommunications wavelengths are much less bright than those with visible-range photons, due to the wavelength dependence of the down-conversion efficiency [38].Integrated photon sources can surpass these limits, as the waveguide, rather than spatial phasematching, defines the allowed modes into which photons are emitted [39]. Singlespatial-mode waveguides in particular completely decouple the brightness from the focusing conditions [40], and can be produced with appropriate choice of the waveguide width and height. Then the the maximum coupling efficiency depends only on the mode ov...

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Analyzing Quantum Error Resilience for Quantum Communication in Guided and Unguided Media

Sihare

2024

Adv Quantum Tech

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This research examines quantum key distribution and its applications in guided and unguided quantum communication. The importance of secure communication in the quantum era requires a thorough exploration of both guided and unguided quantum communication strategies. The research aims to address the challenges posed by guided channels, such as fiber optics, and unguided channels, such as free‐space quantum communication. This study addresses existing knowledge gaps in quantum error resilience management and signal processing techniques in unguided quantum communication. Advanced quantum gate analysis, environmental noise analysis, and quantum channel modeling techniques are employed. The research presents key findings on the impact of gate imperfections on quantum error resilience in guided media, the influence of noise‐induced errors in unguided media, and a unified metric for assessing various error sources in guided channels. Additionally, the study analyses stabilizer codes and surface codes for error mitigation through quantum error correction strategies. Simulation results provide a benchmark for theoretical predictions and guide the refinement of quantum communication protocols. In this context, machine learning‐based error prediction is introduced as a cutting‐edge approach to enhance the robustness of quantum communication systems.

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Fully guided-wave photon pair source for quantum applications

Cited by 43 publications

References 55 publications

Recovering the full dimensionality of hyperentanglement in collinear photon pairs

Recovering the full dimensionality of hyperentanglement in collinear photon pairs

High-performance source of spectrally pure, polarization entangled photon pairs based on hybrid integrated-bulk optics

Analyzing Quantum Error Resilience for Quantum Communication in Guided and Unguided Media

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