15 research outputs found
Optical Quantum Random Number Generator
A physical random number generator based on the intrinsic randomness of
quantum mechanics is described. The random events are realized by the choice of
single photons between the two outputs of a beamsplitter. We present a simple
device, which minimizes the impact of the photon counters' noise, dead-time and
after pulses.Comment: 3 pages + 1 figur
Fast and User-friendly Quantum Key Distribution
Some guidelines for the comparison of different quantum key distribution
experiments are proposed. An improved 'plug & play' interferometric system
allowing fast key exchange is then introduced. Self-alignment and compensation
of birefringence remain. Original electronics implementing the BB84 protocol
and allowing user-friendly operation is presented. Key creation with 0.1 photon
per pulse at a rate of 486 Hz with a 5.4% QBER - corresponding to a net rate of
210Hz - over a 23 Km installed cable was performed.Comment: 21 pages, 6 figures, added referenc
Sine gating detector with simple filtering for low-noise infra-red single photon detection at room temperature
We present and analyze a gated single photon avalanche detector using a sine
gating scheme with a simple but effective low-pass filtering technique for fast
low-noise single photon detection at telecom wavelength. The detector is
characterized by 130 ps short gates applied with a frequency of 1.25 GHz,
yields only 70 ps timing jitter and noise probabilities as low as 7E-7 per gate
at 10% detection efficiency. We show that the detector is suitable for high
rate quantum key distribution (QKD) and even at room temperature it could allow
for QKD over distances larger than 25 km.Comment: 6 pages, 11 figure
Free Running Single Photon Detection based on a negative feedback InGaAs APD
InGaAs/InP-based semiconductor avalanche photodiode are usually employed for
single-photon counting at telecom wavelength. However they are affected by
afterpulsing which limits the diode performance. Recently, Princeton Lightwave
has commercialised a diode integrating monolithically a feedback resistor. This
solution effectively quenches the avalanche and drastically reduces
afterpulsing. Here, we report the development and characterization of a
detector module based on this diode, implementing an active hold-off circuit
which further reduces the afterpulsing and notably improves the detector
performances. We demonstrate free-running operation with 600 Hz dark count rate
at 10% detection efficiency. We also improved the standard double-window
technique for the afterpulsing characterization. Our algorithm implemented by a
FPGA allows to put the APD in a well-defined initial condition and to measure
the impact of the higher order afterpulses.Comment: 18 pages, 15 figures. Submitted to Journal of Modern Optic
1 Mbps coherent one-way QKD with dense wavelength division multiplexing and hardware key distillation
We present the latest results obtained with a quantum cryptography prototype based on a coherent-one way quantum key distribution (QKD) scheme. To support its continuous high rate secret key generation we developed different low-noise single photon detectors for telecom wavelength based on a sine gating and low-pass-filtering technique, as well as a negative feedback APD in an active hold-off circuit. A newly developed hardware distillation engine allows for continuous operation of secret key distribution up to 1 Mbps. We also present results of our system in a DWDM (dense wavelength-division multiplexing) configuration where only one single fiber is needed to interconnect Alice’ and Bob’s systems. The final prototype is fully compatible to serve a high-speed encryption device developed in parallel which provides encrypted communication of up to 100 Gbps