Quantum Communications in space using satellites Giuseppe Vallone , - PowerPoint PPT Presentation

Quantum Communications in space using satellites Giuseppe Vallone , D. Bacco, D. Dequal, S. Gaiarin, M. Schiavon, M. Tomasin, V. Luceri, G. Bianco and P . Villoresi "Fundamental and Quantum Physics with Lasers" Workshop LNF - Frascati, 23 October 2014

Intro QC Results QKD Perspectives Conclusions Summary Introduction and motivations 1 2 Quantum communication in space Results 3 4 QKD scheme Perspectives 5 6 Conclusions Pag. 2

Intro QC Results QKD Perspectives Conclusions Summary Introduction and motivations 1 2 Quantum communication in space Results 3 4 QKD scheme Perspectives 5 6 Conclusions Pag. 3

Intro QC Results QKD Perspectives Conclusions What is Quantum Communication? I Quantum Communications is the ability of faithful transmit quantum states between two distant locations I Ground QC have progressed up to commercial stage using fiber-cables I Quantum Communications on planetary scale require complementary channels including ground and satellite links Pag. 4

Intro QC Results QKD Perspectives Conclusions Motivation Why free-space quantum communications? Pag. 5

Intro QC Results QKD Perspectives Conclusions Motivation Why free-space quantum communications? I Creation of a worldwide quantum network : overcome fiber-loss limitations Pag. 5

Intro QC Results QKD Perspectives Conclusions Motivation Why free-space quantum communications? I Creation of a worldwide quantum network : overcome fiber-loss limitations I Explore the limits of Quantum Mechanics and quantum correlations over very long distances Pag. 5

Intro QC Results QKD Perspectives Conclusions Context I On May 24, 2014 Japan’s NICT launched SOTA on Socrates satellite. I Ongoing programs for QC on satellite in China and Canada as well as in Singapore and USA. Pag. 6

Intro QC Results QKD Perspectives Conclusions Summary Introduction and motivations 1 2 Quantum communication in space Results 3 4 QKD scheme Perspectives 5 6 Conclusions Pag. 7

Intro QC Results QKD Perspectives Conclusions Timeline UniPD Space QComms University of Padova operated at Matera Laser Ranging Observatory, owned by the Italian Space Agency and directed by Dr. Giuseppe “Pippo” Bianco. P. Villoresi et al. New J. Phys. 10 033038 (2008) Pag. 8

Intro QC Results QKD Perspectives Conclusions Objectives I To simulate a quantum source in Space using orbiting retroreflectors I To demonstrate the measurement of quantum states in the downlink I To address the mitigation of the background noise I To demonstrate quantum communication of a generic qubits from Space to ground I To envisage the exploitation of this type of link Pag. 9

Intro QC Results QKD Perspectives Conclusions MLRO facility Matera Laser Ranging Observatory (MLRO): 1.5 m telescope with millimeter resolution in SLR research hub for Space QC since 2003 Dome Laser Pag. 10

Intro QC Results QKD Perspectives Conclusions The making of the qubits CCR: Corner-Cube I Source on satellite simulated by a CCR Retroreflector I Source (Alice) need to be at the single photon level I Downlink attenuation from ⇠ 3 cm LEO sources in the range of 55-70 dB. I Short pulses necessary for background rejection I Not too short to prevent bandwidth opening and noise increasing Pag. 11

Intro QC Results QKD Perspectives Conclusions The making of the qubits I MLRO master laser provided the solution: 100 MHz, 100 ps, 300 mW, 1064 nm I Second harmonics needed for qubits I First order (6.2 µ m ) PPLN I MgO doped Congruent Lithium Niobate - 50 mm – thermally stabilized. Pag. 12

Intro QC Results QKD Perspectives Conclusions Setup Pag. 13 G. Vallone et al. , Experimental Satellite Quantum Communications , [arXiv:1406.4051]

Intro QC Results QKD Perspectives Conclusions Coudé path of in-and-out I Characterization of the polarization transformation I Assessment of total transmission efficiency I Mutual alignement of SLR and Qubit beams Pag. 14 G. Vallone et al. , Experimental Satellite Quantum Communications , [arXiv:1406.4051]

Intro QC Results QKD Perspectives Conclusions Measuring the qubits I The Coudé path is used in both directions for both the SLR beam and the qubits I The upward and inward beams are combined using a non polarizing beam splitter (BS) I Two large ares SPADs mounted to the exit ports, designed to address the velocity-aberration I 81 ps timetagging of 8 channels Pag. 15 G. Vallone et al. , Experimental Satellite Quantum Communications , [arXiv:1406.4051]

Intro QC Results QKD Perspectives Conclusions Summary Introduction and motivations 1 2 Quantum communication in space Results 3 4 QKD scheme Perspectives 5 6 Conclusions Pag. 16 G. Vallone et al. , Experimental Satellite Quantum Communications , [arXiv:1406.4051]

Intro QC Results QKD Perspectives Conclusions Single passage of LARETS Orbit height 690 km - spherical brass body 24 cm in diameter, 23 kg mass, 60 Metallic coated Corner-Cube Retroreflectors Apr 10th, 2014, start 4:40 am CEST Time (s) 0 50 100 150 200 250 300 1,600 Satellite distance (km) | R ⟩ | H ⟩ 1,400 | V ⟩ 1,200 | L ⟩ 1,000 20 Det | H ⟩ Det | H ⟩ Det | L ⟩ Det | L ⟩ 10 Counts 0 10 Det | V ⟩ Det | V ⟩ Det | R ⟩ Det | R ⟩ 20 − 2 − 1 0 1 2 − 2 − 1 0 1 2 − 2 − 1 0 1 2 − 2 − 1 0 1 2 ∆ =t meas − t ref (ns) Detection of four polarization states received from satellite 10 s windows: arrival time within 0 . 5 ns from predictions Pag. 17 G. Vallone et al. , Experimental Satellite Quantum Communications , [arXiv:1406.4051]

Intro QC Results QKD Perspectives Conclusions Link Budget and photon return rate 5 10 Ajisai 4 10 Radar equation for the prediction of 3 10 detected number of photons per pulse 2 10 1 10 1,600 2,100 2,600 5 10 UPLINK Jason − 2 4 10 3 10 ✓ ◆ Frequency (Hz) 1 2 µ sat = µ tx η tx G t ρ A eff Σ T a 10 4 π R 2 1 10 1,600 2,100 2,600 5 10 DOWNLINK Larets 4 10 3 ✓ ◆ Σ 1 10 T a A t η rx η det 2 10 µ rx = µ sat 4 π R 2 ρ A eff 1 10 1,000 1,400 1,800 5 10 Radar equation model provides a precise Starlette 4 10 Stella fit for the measured counts and the µ sat 3 10 2 10 value for the different satellites 1 10 1,000 1,400 1,800 Satellite distance (km) Pag. 18 G. Vallone et al. , Experimental Satellite Quantum Communications , [arXiv:1406.4051]

Intro QC Results QKD Perspectives Conclusions QBER: Quantum Bit Error Rate Ajisai Ajisai 100 Q d =39.2 ± 0.8% µ =3,432 ± 42 Non polarization maintaining CCR: ¯ Q n =39.2 ± 0.8% f =(1,964 ± 24)Hz 50 Polarization Q-Comm not possible 0 Jason − 2 30 Q d =6.0 ± 1.4% Quantum Bit Error Rate (%) µ =1.8 ± 0.1 ¯ Q n =1.8 ± 0.1% f =(100 ± 6)Hz 20 10 0 Larets 30 Q d =1.2 ± 0.1% µ =4.4 ± 0.5 ¯ f =(112 ± 13)Hz 20 Jason-2, Larets, Starlette, Stella 10 0 Polarization maintaining CCR: Starlette 30 Q d =4.3 ± 1.2% µ =2.6 ± 0.2 I QBER compatible with applications ¯ Q n =3.4 ± 1.0% f =(346 ± 21)Hz 20 10 I Demonstration of stable QBER over 0 Stella extended link duration 30 Q d =6.8 ± 2.3% µ =1.3 ± 0.1 ¯ Q n =5.0 ± 1.9% f =(149 ± 15)Hz 20 10 0 0 10 20 30 Elapsed time (s) Pag. 19 G. Vallone et al. , Experimental Satellite Quantum Communications , [arXiv:1406.4051]

Intro QC Results QKD Perspectives Conclusions Summary Introduction and motivations 1 2 Quantum communication in space Results 3 4 QKD scheme Perspectives 5 6 Conclusions Pag. 20 G. Vallone et al. , Experimental Satellite Quantum Communications , [arXiv:1406.4051]

Intro QC Results QKD Perspectives Conclusions QKD: quantum key distribution I A novel approach towards unconditionally secure communications I Exploit quantum mechanics laws for establishing secure keys I Single photon transmission for create keys and classical channel for send encrypted message Pag. 21 G. Vallone et al. , Experimental Satellite Quantum Communications , [arXiv:1406.4051]

Intro QC Results QKD Perspectives Conclusions New QKD satellite protocol using retroreflectors On the base of this experiment, we propose a two-way QKD protocol for space channels: Pag. 22 G. Vallone et al. , Experimental Satellite Quantum Communications , [arXiv:1406.4051]

Intro QC Results QKD Perspectives Conclusions New QKD satellite protocol using retroreflectors On the base of this experiment, we propose a two-way QKD protocol for space channels: I In the ground station, a linearly polarized train of pulses is injected in the Coudé path Pag. 22 G. Vallone et al. , Experimental Satellite Quantum Communications , [arXiv:1406.4051]

Intro QC Results QKD Perspectives Conclusions New QKD satellite protocol using retroreflectors On the base of this experiment, we propose a two-way QKD protocol for space channels: I In the ground station, a linearly polarized train of pulses is injected in the Coudé path I The beam is directed toward a satellite with CCRs having a Faraday Rotator (or equivalent), that rotate the returning polarization by θ , according to QKD protocol Pag. 22 G. Vallone et al. , Experimental Satellite Quantum Communications , [arXiv:1406.4051]