Economic Stimulus : Valorization of Single Photon Detectors and Quantum Key Distribution Systems Hugo Zbinden Group of Applied Physics (GAP), UNIGE NCCR Transfert Projects (GAP – id Quantique): High Speed Single Photon Counting Module (H.Z.) Second Generation QKD Engine (N. Gisin)

ID Quantique Encryption Business Unit Instrumentation Business Unit Spin-off from GAP based in Geneva Founded in employees ( 4 from GAP) Customer base on 6 continents Technology - Single-photon detectors Two product lines - High-Speed Encryption - Quantum Cryptography RNG Business Unit Services (training, installation, maintenance) Services (training, installation, maintenance) 3 business units

NCCR-QP Project 4: Single Photon Detectors 1.InGaAs Avalanche photon detectors 2.Supraconducting Detectors 3.Hybrid schemes: Upconversion detectors, photon number resolving etc

Performance:  = 10-20% P dark = 1000/s Timing jitter = 300 ps Max. Rate = 100 kHz Si-APD: 50 % c dark = 10/s 50 ps 10 MHz InGaAs Avalanche Photo Diode

Afterpulsing is a problem Mitigation: - deadtime - rapid quenching or short gates -> limited count rate, duty cycle < 1

Sinus gating allows high count rates Pulse rate 1.25 GHz, gate width ~130ps (FWHM)

Novel APD with negative feedback for free running operation  Internal resistor quenches rapidly the avalanche  Slow recharging  -> nice results in free running mode: poster of Tommaso Lunghi

Versatile detector module Specifications:  Gated mode up to 100 MHz  Variable gate length 1ns to 10ns  Free running  Integrated counters, clock, variable delay etc  Inputs and outputs in NIM, ECL, TTL etc  «cool» user interface  Easy upgradable with new functions (TDC, histogram)

id 210 as a whole People:Jun Zhang (physicist), APD characterisation, measurements Claudio Barreiro (engineer), pulser electronics Oliver Guinnard (engineer), design, electronics, mechanics Bernard Clausen (engineer), electronics Alexis Rochas (physicist), concept and testing Jean-Benoit Page (engineer), programming, user interface Laurent Monat (engineer), electronics and FPGA Tony Matteo (engineer), production

The Result:

Quantum Key Distribution  Quantum Cryptography is not a new coding method, it allows to create a secret key  Security is based on the laws of quantum physics “A measurement perturbs the system in an irreversible way”. A spy listening to the “quantum communication”, disturbs the system and will be detected.

The basic idea is simple Alice EveBob Error with 25 % probability ÞThe error rate (QBER) indicates the presence of Eve and the information she possesses (in practice typical QBER ~1-2%)

Key Distillation AliceBob Quantum channel Public channel (losses) Qubits Transmission Basis Reconciliation QBER estimate Error correction Privacy amplification Sifted key Raw key Key

Smolin and Bennett IBM 1989 id Quantique (dark) fibers Distance  100km 100 MHz Ethernet Not One Time Pad!

The plug & play system is getting old  Faint laser BB 84, two way scheme  5 MHz pulse rate  1 kbit/s secret bit 25km presented at CeBit 02 with guest star Sandra Pochon!

-Coherent faint laser pulses (µ~0.5) -150 km of installed and standard fibres, 43dB of losses -SECOQC 2008 (Vienna) Coherent-One-Way (COW) scheme

Industrial COW prototype: 1000 times higher bit rates  625 MHz rate (1.25 GHz pulse rate)  1 Mbit/s secret key 25km  WDM of quantum and classical channel  real time distillation (FPGA)  security, finite key analysis

The QCrypt Concept 100 Gb/s 1 Mb/s OTP High-speed Quantum Key Distribution + 40 – 100Gbps enCRYPTion + WDM

QKD Engine Results: 250 ps  T fwhm =138 ps Intensity modulation Sinus gating detector Short gates Low afterpulsing High count rates

QKD and WDM  Goal: Key distribution and high speed data encryption over a single optical fibre  Commercial QKD (plug & play) and AES-encryptors (256 bits keys, 1 Gbps rate) New Journal of Physics 12 (2010) Classical communication channel Dedicated quantum channel AliceBobAliceBob

Experimental Results Fiber attenuation: dB/km Detection efficiency: 0.07 Dark count rate: 5  ns -1 Dead time: 10  s DWDM isolation: 82 dB

Thank you for your attention