855 research outputs found
Field test of quantum key distribution in the Tokyo QKD Network
A novel secure communication network with quantum key distribution in a
metropolitan area is reported. Different QKD schemes are integrated to
demonstrate secure TV conferencing over a distance of 45km, stable long-term
operation, and application to secure mobile phones.Comment: 21 pages, 19 figure
Getting routers out of the core: Building an optical wide area network with "multipaths"
We propose an all-optical networking solution for a wide area network (WAN)
based on the notion of multipoint-to-multipoint lightpaths that, for short, we
call "multipaths". A multipath concentrates the traffic of a group of source
nodes on a wavelength channel using an adapted MAC protocol and multicasts this
traffic to a group of destination nodes that extract their own data from the
confluent stream. The proposed network can be built using existing components
and appears less complex and more efficient in terms of energy consumption than
alternatives like OPS and OBS. The paper presents the multipath architecture
and compares its energy consumption to that of a classical router-based ISP
network. A flow-aware dynamic bandwidth allocation algorithm is proposed and
shown to have excellent performance in terms of throughput and delay
Quantum key distribution over multicore fiber
We present the first quantum key distribution (QKD) experiment over multicore fiber. With space division multiplexing, we demonstrate that weak QKD signals can coexist with classical data signals launched at full power in a 53 km 7-core fiber, while showing negligible degradation in performance. Based on a characterization of intercore crosstalk, we perform additional simulations highlighting that classical data bandwidths beyond 1Tb/s can be supported with high speed QKD on the same fiber.S.J.K. acknowledges support from the EPSRC CDT in Photonic Systems Development
Unrepeatered field transmission of 2 Tbit/s multi-banded coherent WDM over 124 km of installed SMF
In this paper we report field transmission of a 2Tbit/s multi-banded Coherent WDM signal over BT Ireland's installed SMF, using EDFA amplification only, with mixed Ethernet (with FEC) and PRBS payloads. To the best of our knowledge, the results obtained represent the highest total capacity transmitted over installed SMF with orthogonal subcarriers. BERs below 10(-5) and no frame-loss were recorded for all 49 subcarriers. Extended BER measurements over several hours showed fluctuations that can be attributed to PMD and to dynamic effects associated with clock instabilities
Network of Time-Multiplexed Optical Parametric Oscillators as a Coherent Ising Machine
Finding the ground states of the Ising Hamiltonian [1] maps to various
combinatorial optimization problems in biology, medicine, wireless
communications, artificial intelligence, and social network. So far no
efficient classical and quantum algorithm is known for these problems, and
intensive research is focused on creating physical systems - Ising machines -
capable of finding the absolute or approximate ground states of the Ising
Hamiltonian [2-6]. Here we report a novel Ising machine using a network of
degenerate optical parametric oscillators (OPOs). Spins are represented with
above-threshold binary phases of the OPOs and the Ising couplings are realized
by mutual injections [7]. The network is implemented in a single OPO ring
cavity with multiple trains of femtosecond pulses and configurable mutual
couplings, and operates at room temperature. We programed the smallest
non-deterministic polynomial time (NP)- hard Ising problem on the machine, and
in 1000 runs of the machine no computational error was detected
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Lights, fiber, action! A primer on in vivo fiber photometry
Fiber photometry is a key technique for characterizing brain-behavior relationships in vivo. Initially, it was primarily used to report calcium dynamics as a proxy for neural activity via genetically encoded indicators. This generated new insights into brain functions including movement, memory, and motivation at the level of defined circuits and cell types. Recently, the opportunity for discovery with fiber photometry has exploded with the development of an extensive range of fluorescent sensors for biomolecules including neuromodulators and peptides that were previously inaccessible in vivo. This critical advance, combined with the new availability of affordable “plug-and-play” recording systems, has made monitoring molecules with high spatiotemporal precision during behavior highly accessible. However, while opening exciting new avenues for research, the rapid expansion in fiber photometry applications has occurred without coordination or consensus on best practices. Here, we provide a comprehensive guide to help end-users execute, analyze, and suitably interpret fiber photometry studies
Progress on Integrating Quantum Communications in Optical Systems Testbeds
Experimental methods are being developed to enable quantum communication
systems research in testbeds. We describe testbed architectures for emerging
quantum technologies and how they can integrate with existing fibre optical
testbeds, specifically OpenIreland.Comment: 5 pages, 2 tables, 1 figure, Asia Communications and Photonics
Conference 202
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