— In this work we present the principles and experimental demonstration of a BB84 Quantum Key Distribution (QKD) one way system using fainted pulses and a Quadrature Phase-Shift-Keying (QPSK) format including a time-multiplexed unmodulated carrier reference at Alice's end, and a differential homodyne reception at Bob's end. We also describe the secure… (More)
In this paper, we present the prototype of an ATPsystem intended to be used in an optical quantum communications link between a Cubesat and an optical earth station. The ATP system is designed in such way that alignment on the satellite with respect to the optical earth station will be carried out based on the concept of an artificial star with the help of… (More)
resistive losses. Figure 3 shows the chip photo of the fabricated CR-LNA with a chip area of 0.59 mm 2 including all testing pads. Note that the 15-pF capacitor (C 3) is implemented by an array of capacitors, and it consumes about 120 3 180 lm 2 chip area. The CR-LNA consumes 5.5 mW from a 1.3-V supply voltage , and undesired parasitics of pads and… (More)
In this work we first present the SATEX 1 microsatellite project, as our initial experience in space optical communications; we then describe the current activities on the design and development of the SENSAT 1 nanosatellite and especially its optical communications payload, consisting of an 830 nm downlink optical transmitter for data communications, with… (More)
In this work we present the principles of a flexible quantum key distribution (QKD) system using quadrature-phase-shift-keying (QPSK) base and symbol encoding and dual-threshold balanced homodyne detection (BHD) scheme. We give its security proofs and we compare its performance experimentally with a photon counting detection scheme.