5 research outputs found
Studies on the readability and on the detection rate in a Mach-Zehnder interferometer-based implementation for high-rate, long-distance QKD protocols
We study the way that chromatic dispersion affects the visibility and the
synchronization on Quantum Key Distribution (QKD) protocols in a widely-used
setup based on the use of two fiber-based Mach-Zehnder (MZ) interferometers at
transmitter/receiver stations. We identify the necessary conditions for the
path length difference between the two arms of the interferometers for
achieving the desired visibility given the transmission distance -- where the
form of the detector's window can be considered. We also associate the above
limitations with the maximum detection rate that can be recorded in our setup,
including the quantum non-linearity phenomenon, and to the maximum time window
of the detector's gate. Exploiting our results we provide two methods,
depending on the clock rate of the setup, to perform chromatic dispersion
compensation techniques to the signal for keeping the correct order of the
transmitted symbols. At the end, we apply our theoretical outcomes in a more
realistic QKD deployment, considering the case of phase-encoding BB84 QKD
protocol, which is widely used. Our proposed methods, depending on the
transmission distance and on the photon emission rate at transmitter station,
can be easily generalized to every fiber-optic QKD protocol, for which the
discrimination of each symbol is crucial.Comment: 14 pages, 12 figure
All-silicon quantum light source by embedding an atomic emissive center in a nanophotonic cavity
Silicon is the most scalable optoelectronic material, and it has
revolutionized our lives in many ways. The prospect of quantum optics in
silicon is an exciting avenue because it has the potential to address the
scaling and integration challenges, the most pressing questions facing quantum
science and technology. We report the first all-silicon quantum light source
based on a single atomic emissive center embedded in a silicon-based
nanophotonic cavity. We observe a more than 30-fold enhancement of
luminescence, a near unity atom-cavity coupling efficiency, and an 8-fold
acceleration of the emission from the quantum center. Our work opens avenues
for large-scale integrated all-silicon cavity quantum electrodynamics and
quantum photon interfaces with applications in quantum communication, sensing,
imaging, and computing
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Scalable manufacturing of quantum light emitters in silicon under rapid thermal annealing.
Quantum light sources play a fundamental role in quantum technologies ranging from quantum networking to quantum sensing and computation. The development of these technologies requires scalable platforms, and the recent discovery of quantum light sources in silicon represents an exciting and promising prospect for scalability. The usual process for creating color centers in silicon involves carbon implantation into silicon, followed by rapid thermal annealing. However, the dependence of critical optical properties, such as the inhomogeneous broadening, the density, and the signal-to-background ratio, on centers implantation steps is poorly understood. We investigate the role of rapid thermal annealing on the dynamic of the formation of single color centers in silicon. We find that the density and the inhomogeneous broadening greatly depend on the annealing time. We attribute the observations to nanoscale thermal processes occurring around single centers and leading to local strain fluctuations. Our experimental observation is supported by theoretical modeling based on first principles calculations. The results indicate that annealing is currently the main step limiting the scalable manufacturing of color centers in silicon