In the frame of the Secure And cryptoGrAphic (SAGA) project under ESA ARTES 4.0 program, we report the design and the test of a High-Performance Entangled Photon Source (HP-EPS) dedicated to QKD satellite-based communication, by using the Conventional-band optical fiber telecom components. We developed an asynchronous time binning higher than 10 bits/sec and 5 bits/sec for respectively a 60 dB (LEO) and a 65 dB (GEO) transmission loss budgets (both downlinks combined). The compactness and simplicity of the optical design, the low electrical consumption and the low mass combined with the robustness of the all-fibered design to the space environment (mechanical vibrations, shock, and radiations) make the HP-EPS a valuable and serious candidate for the satellite-based QKD quest.
Photon entanglement has appeared to play a crucial role in the foundation of quantum physics and in the ever-increasing requirements of quantum information processing, quantum communication, quantum sensing and quantum computing. Thus, the industrial development and the characterization of practical entangled photon sources at telecom wavelengths are key element for the deployment of emerging quantum applications, such as Quantum Key Distribution.
The photon source is based on a 775 nm pumped type II Periodically Poled Lithium Niobate wave guide (PPLN_WG) designed for generation of orthogonally polarized photon pairs at 1550 nm. Picometer tunability of the converted central wavelength is achieved by using an accurate temperature control of both the PPLN_WG and the laser diode. All optical and electronics elements are embedded in a compact module. This practical photon source is driven by a USB communication port compatible with computer. The main characteristics of the photon source, Coincidence-to-Accidental-Ratio (CAR), brightness, bi-photon spectrum, heralded efficiency, purity, and indistinguishability are measured by using integrated optical benches and a 2-channels very-low-noise InGaAs single photon avalanche counters (G-SPAD). The proposed photon source measurements protocol is also available for the characterization of other photon sources technologies, such as for the Quantum Dots and semiconductor photon sources.
We performed two experimental Bell inequality violations by creating polarization entanglement or by using the natural frequency entanglement of our source. Violation by more than five standard deviations Bell inequalities with our setups demonstrate that our photon source is a promising tool for the realization of various distances quantum information experiments.
Advanced manufacture of DWDM multidielectric narrow-band optical filters designed for broadband technologies are presented and discussed. Three-cavity structures of 2 nm half- maximum bandwidth pass-band filters in the 1550 nm range with more than 94% at peak transmission and 4 nm width at 20 dB of attenuation is presented. It has been designed for 400 GHz channel spacing.
The increasing demand of complex micro-optical products such as Diffractive Optical Elements (DOE) requires the development of new optical material processing micro- techniques especially for small-series production. Diamond turning machining is considered an ideal, mature production tool of DOE in ductile materials but not brittle ones. However, the progress in optical material UV-laser machining is proving to be a good candidate for the micro-structuring of glasses. Thus, by using this emergent UV-laser machining technique, DOE prototypes in C2036 have been made and show promising results.
KEYWORDS: Clouds, LIDAR, Signal attenuation, Mass attenuation coefficient, Visibility through fog, Visibility, Solid state lasers, Fiber optic gyroscopes, Signal detection, Transmitters
A cloud base height indicator using a single pulse solid state laser, called ALTO, has been developped for aeronautical purposes by SOPELEM-SOFRETEC company in association with the French Meteorological Office. Meteo-France investigates a method to obtain a vertical profile of atmospheric extinction coefficient. This method is used to determine cloud height, to locate backscattering layers and to allow the identification ofthe hydrometeor nature in the lower part ofthe atmosphere (mist, fog or precipitation). The performances of this equipment in term of LIDAR capabilities were presented in detail in a previous paper 1,
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