metrology for quantum cryptography: the european effort
TRANSCRIPT
http://www.etsi.org/technologies-clusters/technologies/quantum-key-distribution
The Industry Specification Group (ISG) on Quantum Key Distribution (QKD) of the European Telecommunications Standards Institute (ETSI ISG-QKD) is addressing standardisation issues in quantum cryptography, and quantum technology in general
QUANTUM PHOTONIC TECHNOLOGIES
Started from the outcome of the EC FP6-project SECOQC (Secure Communication based on Quantum Cryptography), an Industry Specification Group (ISG) of the European Telecommunications Standards Institute (ETSI).
Applied Communication SciencesAustrian Institute of Technology (AIT)BMWi - Federal Ministry of Economics and TechnologyCadzow Communications Consulting Ltd (UK)DCMS Department for culture, Media and Sport Organization ( former BIS)Facultad de Informatica, Universidad Politecnica de MadridHewlett-Packard, Centre de CompƩtences FranceInstitut Mines TelecomIstituto Nazionale di Ricerca Metrologica (INRIM)Mitsubishi Electric RCENational Institute of Information and Communications Technology (NICT)NTT CorporationSWISSCOM SATELEFONICA S.A.THALESTOSHIBA RESEARCH EUROPE LTDTubitak UekaeUniversida Politecnica de MadridUniversity of Waterloo
Arche Finanz GmbHID Quantique SASK Telecom
JRP EXL02 - SIQUTE
Squqis
ā¦ā¦.
IND06: Metrology for Industrial Quantum Communicationshttp://www.miqc.org/
Objective: development of a pan-European measurement infrastructure (standards,measurement facilities, ā¦) for practical QKD system
ā¢ QKD components require independent characterisation in order to convince end-users that the technology is working within specification
ā¢ 3 year project (ended Aug 2014)
Towards Radiometric Quantum Standards
Photon emitters Traceable characterisation of commercial QKD sources:ā¢ Attenuated laser pulses
Photon receiversTraceable calibration of commercial QKD receivers:ā¢ Gated photon counting detectors
Key Measurement Outputs of MIQC
Quantum channel (optical fibre) and RNG ā¢ Traceable characterisation of single mode optical fibreā¢ Characterisation of propagation of photon state in single mode fibreā¢ Open system true physical quantum random number generator (QRNG)ā¢ QRNG physically characterised and tested under different operating
conditions
Phase encoded, attenuated laser pulse QKD over fibre at 1550 nm
Detectorsā parameters considered [1/2]Parameter Symbol Units Definition Measurement approach
Photon detectionprobability
h probability/gate
The probability that a photon incident at the optical input will be detected within a detection gate.
Via a calibrated laser light source and a calibrated filter
Dark countprobability
Pdark (probability/gate)
The probability that a detector registers a detection event per gate, despite the absence of optical illumination.
As above (1)
Afterpulse probability Pafterpulse (probability/gate)
The probability that a detector registers a false detection event in the absence of illumination, conditional on a true photon detection event in the preceding detection gate.
As above (1)
Dead time Tdead ns/Āµs The smallest time duration after which the detection efficiency is independent of previous photon detection history.
Via a train of two optical pulses with tuneable temporal separation
Recovery Time Trec ns/Āµs The time duration after a photon detection event for the detection efficiency to return to 99% of its steady-state value. This is only important if the detector is passively quenched
As above (4)
Receiverās Detectors
Detectorsā parameters considered [2/2]Parameter Symbol Units Definition Measurement approach
Maximum count rate Cmax MHz/GHz The maximum rate of photon detection events under strong illumination condition in the single/few photon/gate regime.
This will be determined by the photon detection efficiency, the dead time, and dark counts
Timing jitter Tjitter ps/ns The uncertainty in determining the arrival time of a photon at the optical input.
Measure the FWHM in the distribution of detection times
Maximum clock frequency
Fmax MHz/GHz The maximum clock frequency at or below which a detector can be operated in a QKD system without giving rise to an intolerable bit error rate.
Spectral Responsivity Rs unitless The photon detection efficiency as a function of wavelength of the incident photons.
Via a calibrated laser light source with known wavelength (wavemeter) and a calibrated filter
Receiverās Detectors
Detection probability
Photon Detection Probability
Detection efficiency of the InGaAs-SPAD
pulsed@1,55 Āµm
Laserattenuators-30dB ā¦-60 dB
counter
pulse/delaygenerator
amplifier + VoltmeterCalibrated InGaAs-DiodeIssues
- Attenuators Calibration From CW to pulsed source - Nonlinearity & Deadtimes- From CW to pulsed source- ā¦
Optical power traceability chain (SI)
0.005 % uncertainty
visible wavelengths,0.5 mW,collimated, free-space laser radiation
1 % uncertainty (k = 2)
1550 nm,100 pW,output from optical fibre
Primary standardCryogenic radiometry
NMI reference detectors
Low power reference detector
Photon emitters Traceable characterisation of commercial QKD sources:ā¢ Attenuated laser pulses
Photon receiversTraceable calibration of commercial QKD receivers:ā¢ Gated photon counting detectors
Key Measurement Outputs of MIQC
Quantum channel (optical fibre) and RNG ā¢ Traceable characterisation of single mode optical fibreā¢ Characterisation of propagation of photon state in single mode fibreā¢ Open system true physical quantum random number generator (QRNG)ā¢ QRNG physically characterised and tested under different operating
conditions
Phase encoded, attenuated laser pulse QKD over fibre at 1550 nm
Source parameters considered [1/2]Parameter Symbol Units Definition Measurement approachFrequency (Rep.Rate)
F Hz The frequency set by the pulse generator
Measure via standard traceable frequency calibration techniques
Mean photon number
Āµ Photons/pulse
Average number of photons per pulse emitted by Alice
a) calibrated detector and commercial attenuator
b) calibrated detector and traceable attenuator based on InGaAs photodiodes
c) reconstruction of probability distribution
d) Photon number resolving detector based on commercial single photon detector in tree configuration
Mean photon number variation
ĻĀµ As above
Source timing jitter JS ps or ns The uncertainty in the emission time of a photon at the optical output.
Measure FWHM of distribution of photon emission times with respect to pulse generator signal
Emitterās Sources
Source parameters considered [2/2]Parameter Symbol Units Definition Measurement approachSource wavelength Ī» nm Wavelength of photons
that are emitted.Wavemeter
Spectral line width Ī“ GHz Bandwidth of the emitted photons.
Beat note measurement or Fabry-Perot interferometer.
Spectral indistinguishability
sind Unitless The extent to which the encoded states can be distinguished through spectral measurement.
Fabry-Perot interferometer: compare spectra of differentencoding states
Temporal indistinguishability
tind Unitless The extent to which theencoded states can bedistinguished throughtemporal measurement.
The probability distribution with respect to time for laser output pulses is measured. tind is calculated according to reference [12].
Polarisation state Polarisation reconstruction
Emitterās Sources
Source photon number statistics
i) Calibrated detector and commercial attenuator
Setupā¢ Calibrated power meter can be used to measure flux (approaches detection limit of
power meter)ā¢ Mean photon number measured using calibrated photon-counting detector
(correcting for the non-linear behavior)
( )10 AP
f hcāĀµ =
Ī»Mean photon number:
Source photon number statistics
ii) Reconstruction of probability distribution
Photon number distribution
For on/off detectors like SPAD with quantum efficiency š¼š¼, the probability of no-clicks is:
āON/OFFā Tomography
-Truncating the p.d. to a certain šš-Changing the value of the quantum efficiency šššš
Poissonian
ReconstructedG. Zambra, M. Bondani, A. Andreoni, G. Brida, M. Gramegna, M.G., A. Rossi, M.G.A. Paris , PRL 95, 063602 (2005)
Source photon number statistics
iii) PNR detector based on tree configuration
Detector Tree:4 click/no-click detectors
BS
BS
BS
( )( )
(2) (3) (4) ( ), , 1
nn
P ng g g g
P=
ā¢ By measuring higher-order g(n), it is possible to deconvolvethe underlying number and kind (poissonian, pseudo-termal or single-photon) of occupied modes of a light field.
Deconvolving the p.d. of incoming photons
Goldschmidt et al., PRA 88, 013822 (2013)
ā¢ POVM reconstruction F. Piacentini et al.; Opt. Lett. 40(2015) 1549.
ā¢ Novel (entanglemet-assisted) quantumcharacterisation technique for PNRdetector Brida et al., PRL 108, 253601 (2012)
Noiseless Heralded SPS
HBT
ātswitchg(2) =
ātswitch = 2nsBrida et al., APL 101, 221112 (2012)
Photon emitters Traceable characterisation of commercial QKD sources:ā¢ Attenuated laser pulses
Photon receiversTraceable calibration of commercial QKD receivers:ā¢ Gated photon counting detectors
Key Measurement Outputs of MIQC
Quantum channel (optical fibre) and RNG ā¢ Traceable characterisation of single mode optical fibreā¢ Characterisation of propagation of photon state in single mode fibreā¢ Open system true physical quantum random number generator (QRNG)ā¢ QRNG physically characterised and tested under different operating
conditions
Phase encoded, attenuated laser pulse QKD over fibre at 1550 nm
Optical time-domain reflectometeroperating at single-photon level
PULSE GENERATOR
LASER
ATT 1:99
DUT
OTDR operating at single-photon level
PULSE GENERATOR
LASER
ATT 1:99
DUT
0 50 100 150 2001
10
100
1000
Coun
ts
t/ns
Backscattered Signal
FUTURE PERSPECTIVES
ā¢ MIQC was just the beginning ā¦ā Relevant parameters non-considered (e.g. parameters related
to side-channel attacks, or other QKD hacking technique) ā Open-Air QKD Visibleā Other QKD protocols to be considered (e.g. entanglement
based)ā Producers more involvedā ā¦
MIQC2
MIQC2
QKD with orthogonal states
ā¢ Controfactual Noh QKD protocol
Quantum Bit Error Rate (QBER)QBERS1 = 0,071 Ā± 0,014
QBERS0 = 0,070 Ā± 0,016
PRA 82 (062309 (2010) Las. Phys. Lett. 9 247 (2012)
SPS with colour centres in diamondā¢ "Electroluminescence from a diamond device with
ion-beam-micromachined buried graphitic electrodes", J. Forneris et al.Nuclear Instruments and Methods in Physics Research B 348 (2015) 187.
ā¢ "Single-photon emitters based on NIR color centers in diamond coupled with solidimmersion lenses", D. Gatto Monticone et al. IJQI 12 (2014) 1560011.
ā¢ "Beating the Abbe Diffraction Limit in Confocal Microscopy via Nonclassical PhotonStatisticsĀ» D. Gatto Monticone et al. Phys. Rev. Lett. 113, 143602 (2014)
ā¢ ā¦ā¦..
Goldenberg & Vaidman protocol
INRIM QUANTUM TECH GROUP
8 quantum optics labspermanent staff: M.G., G. Brida, I. Degiovanni, M.Gramegna, I.Ruo Bercheranon permanent staff: G.Adenier,A.Avella, A. Meda, G.Giorgi*, E.Moreva, F. Piacentini, M.Roncaglia*,P.Traina; PhD students: M.Levi,N.Samantaray, S.Pradyumna