Background noise of satellite-to-ground quantum key distribution

Miao, Er-Long; Han, Zheng‐Fu; Gong, Shunsheng; Zhang, Tao; Da-Sheng, Diao; Guo, Guang‐Can

doi:10.1088/1367-2630/7/1/215

Cited by 114 publications

(57 citation statements)

References 30 publications

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“…The biggest source of noise in free-space optical links is represented by environmental light entering in the receiver telescope together with the signal photons. Simple models to estimate the amount of stray light [11,23] are given in appendix C for down-links and up-links. In the following analysis we consider the number of stray photons to be independent of the position of the satellite.…”

Section: Performance Of Qkd Implementationsmentioning

confidence: 99%

“…In the daytime, instead, due to the stronger background light, the key rate vanishes at higher elevation angles, even considering improved spatial, spectral and temporal filtering. According to [23], the typical brightness of the sky background (see also section appendix C) in a clear day is about 3 orders of magnitude higher than during a full-moon night. We found that, in order to achieve a non-zero key rate for a reasonable portion of the transit, the filtering of the stray light must be tighter than during the night of a factor 100, obtained acting on the field of view (FOV) of the telescope and the width of the spectral filters (refer to table E3 in appendix E for details).…”

Section: Performance Of Qkd Implementationsmentioning

confidence: 99%

“…The appendix starts with a recap of the results of [21,22] (appendix A) and their application to the problem at hand (appendix B). Then two models for the estimation of the stray light satellite links [11,23] are presented in appendix C. Appendix D is devoted to the definition of the QKD protocols we use in section 4 and the expression of the correspondent key rates. In appendix E we report the parameters chosen for the simulations and we discuss their pertinence.…”

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confidence: 99%

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Satellite-based links for quantum key distribution: beam effects and weather dependence

2019

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The establishment of a world-wide quantum communication network relies on the synergistic integration of satellite-based links and fiber-based networks. The first are helpful for long-distance communication, as the photon losses introduced by the optical fibers are too detrimental for lengths greater than about 200 km. This work aims at giving, on the one hand, a comprehensive and fundamental model for the losses suffered by the quantum signals during the propagation along an atmospheric free-space link. On the other hand, a performance analysis of different quantum key distribution (QKD) implementations is performed, including finite-key effects, focusing on different interesting practical scenarios. The specific approach that we chose allows to precisely model the contribution due to different weather conditions, paving the way towards more accurate feasibility studies of satellite-based QKD missions. IntroductionQuantum key distribution (QKD) and quantum communication in general have the potential to revolutionise the way we communicate confidential information over the internet. The natural carriers for quantum information are photons, that are already widely used in classical networks of optical fibers to achieve high communication rates. Unfortunately, even though enormous improvements have been obtained in the last years [1, 2], scaling quantum communication protocols over long distances is very challenging, due to the losses experienced during the propagation inside the optical fibers. Several schemes for the realization of quantum repeaters have been proposed in recent years, that could allow to bridge long distances and naturally be implemented inside a quantum communication network [3][4][5][6][7]. Considering the important technological hurdles that quantum repeaters should overcome before becoming useful, satellite-based free-space links look like the most practical way to achieve long-distance QKD in the short term [8]. They can take advantage of the satellite technology and the optical communication methods developed in the last decades in the classical case. Various feasibility studies had addressed this topic in the last twenty years [8][9][10][11] and several experiments have definitely proved that the technology involved is ready for deployment [12][13][14][15][16].Optical satellite-based links have the important drawback of being strongly dependent on the weather conditions [17][18][19][20]. The presence of turbulent eddies and scattering particles like haze or fog generates random fluctuations of the relative permittivity of the air, on different length-and time-scales. This phenomenon affects the light propagation in a complicated way, inducing random deviations and deformations of any optical beam sent through the atmosphere. It results in reduced transmittance, because of geometrical losses due to the finite collection aperture, and random modifications of the phase front. A comprehensive model of these effects is then necessary, in order to precisely evaluate the performance of the link w...

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Section: Performance Of Qkd Implementationsmentioning

confidence: 99%

Section: Performance Of Qkd Implementationsmentioning

confidence: 99%

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confidence: 99%

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Satellite-based links for quantum key distribution: beam effects and weather dependence

2019

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“…Nowadays quantum key distribution (QKD) [1] through atmospheric turbulence channel over long distance has been realized [2][3][4], and satellite-to-ground discrete variable QKD [1] over 1200 km has been verified recently [5]. However, systems using single-photon detectors suffer from background noise [6], while homodyne or heterodyne detection with bright local oscillator (LO) acting as a filter can reduce the background noise [7]. Experiments measuring Stokes operators [8][9][10][11][12][13] have shown the filtering effect of LO.…”

Section: Introductionmentioning

confidence: 99%

Atmospheric effects on continuous-variable quantum key distribution

et al. 2018

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Compared to fiber continuous-variable quantum key distribution (CVQKD), atmospheric link offers the possibility of a broader geographical coverage and more flexible transmission. However, there are many negative features of the atmospheric channel that will reduce the achievable secret key rate, such as beam extinction and a variety of turbulence effects. Here we show how these factors affect performance of CVQKD, by considering our newly derived key rate formulas for fading channels, which involves detection imperfections, thus form a transmission model for CVQKD. This model can help evaluate the feasibility of experiment scheme in practical applications. We found that performance deterioration of horizontal link within the boundary layer is primarily caused by transmittance fluctuations (including beam wandering, broadening, deformation, and scintillation), while transmittance change due to pulse broadening under weak turbulence is negligible. Besides, we also found that communication interruptions can also cause a perceptible key rate reduction when the transmission distance is longer, while phase excess noise due to arrival time fluctuations requires new compensation techniques to reduce it to a negligible level. Furthermore, it is found that performing homodyne detection enables longer transmission distances, whereas heterodyne allows higher achievable key rate over short distances. heterodyne detection. Based on the deduced key rate formula, we consider three key parameters that affect the key rate. First, the transmittance change due to beam extinction [21] and turbulence effects (temporal pulse broadening, beam wandering, broadening, deformation, and scintillation) [22] are considered, where extinction likes the attenuation in an optical fiber. Our results demonstrate that beam wandering, broadening and deformation are the main turbulence effects affecting the achievable key rate. Second, we consider the communication interruption caused by angle-of-arrival fluctuations [20], and we found that the interruption probability is noticeable in the case of long-distance transmission. Third, we estimate the excess noise caused by pulse arrival time fluctuations which is found to be quite large. Based on the impacts mentioned above, we conduct a performance analysis.This paper is organized as follows. In section 2, we deduce the achievable secret key rate over the atmospheric channel. In section 3, with the result of section 2, we show how atmospheric effects affect the performance of GMCS CVQKD. In section 4, We consider all the implications mentioned in section 3 and perform a performance analysis. Finally we come to the conclusion and discussion in section 5.

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“…Although a background noise by sunlight could be reduced to some extent by use of wavelength filter, a background noise component with the wavelength of the signal beam cannot be filtered out. A more efficient noise reduction technique is required for high-speed data transmission [1] . Our system can partially filter out the background light by spatial phase modulation/demodulation and filtering processes using phase compensation by the PCM.…”

Section: Introductionmentioning

confidence: 99%

Optical intersatellite data transmission with phase conjugate mirror for formation flying

et al. 2006

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We propose a new optical intersatellite communications system with a phase conjugate mirror (PCM) in formation flying (FF). In conventional optical intersatellite communications, high-accurate target acquisition and tracking are required for both the transmitter and the receiver. In our system with a PCM, when a control beam from the receiver is captured by a PCM in the transmitter, the signal beam from the transmitter introduced back to the receiver as its phaseconjugate replica. Thus, it is not necessary for the transmitter to target the receiver. Another advantage of using a PCM is that we can utilize spatial filtering. Background noise by sunlight with the laser wavelength can also be efficiently suppressed by a spatial phase modulation/demodulation and filtering processes using phase compensation by the PCM, which leads to the improvement of the signal-to-noise ratio (SNR) and hence provides high data transmission rates in the system. In order to efficiently filter out the background noise, a large beam propagation angle is required in spatial filtering. We spatially modulate the background noise by the diffuser and reduce the beam diameter by the expansion/downscale optical system as a method to enlarge the beam propagation angle.In this paper, we show that our system can separate the noise from the signal by using the expansion/downscale optical system even under spatial phase modulation. In the analysis, the SNR is 32.6[dB] at scale=8.0×10 4 , when a spatial phase modulation by the diffuser is θ=1.5×10 -5 [rad].

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Background noise of satellite-to-ground quantum key distribution

Cited by 114 publications

References 30 publications

Satellite-based links for quantum key distribution: beam effects and weather dependence

Satellite-based links for quantum key distribution: beam effects and weather dependence

Atmospheric effects on continuous-variable quantum key distribution

Optical intersatellite data transmission with phase conjugate mirror for formation flying

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