1,868 research outputs found
Entanglement Distribution in Optical Networks
The ability to generate entangled photon-pairs over a broad wavelength range
opens the door to the simultaneous distribution of entanglement to multiple
users in a network by using centralized sources and flexible
wavelength-division multiplexing schemes. Here we show the design of a
metropolitan optical network consisting of tree-type access networks whereby
entangled photon-pairs are distributed to any pair of users, independent of
their location. The network is constructed employing commercial off-the-shelf
components and uses the existing infrastructure, which allows for moderate
deployment costs. We further develop a channel plan and a network-architecture
design to provide a direct optical path between any pair of users, thus
allowing classical and one-way quantum communication as well as entanglement
distribution. This allows the simultaneous operation of multiple quantum
information technologies. Finally, we present a more flexible backbone
architecture that pushes away the load limitations of the original network
design by extending its reach, number of users and capabilities.Comment: 26 pages, 12 figure
CWDM self-referencing sensor network based on ring resonators in reflective configuration
A new scalable self-referencing sensor network with low insertion losses implemented in Coarse Wavelength Division Multiplexing (CWDM) technology is reported. It allows obtaining remote self-referenced
measurements with a full-duplex fibre downlead up to 35 km long, with no need for optical amplification. Fibre Bragg gratings (FBG) are used in order to achieve a reflective configuration, thus increasing the sensitivity of the optical transducers. Low-cost off-the-shelf devices in CWDM technology can be used to implement and scale the network. Ring resonator (RR) based
incoherent interferometers at the measuring points are used as selfreferencing
technique. A theoretical analysis of power budget of the topology is reported, with a comparison between the proposed network and a conventional star topology. Finally, the new configuration has been experimentally demonstrated.This work has been supported by CICYT:TIC2003-03783, UC3M:FAVICOBIS and CAM:FACTOTEM-CM (S-0505/ESP/000417).Publicad
O-Band Differential Phase-Shift Quantum Key Distribution in 52-Channel C/L-Band Loaded Passive Optical Network
A cost-effective QKD transmitter is evaluated in a 16km reach, 2:16-split PON
and yields 5.10-7secure bits/pulse. Co-existence with 20 down-and 1 upstream
channel is possible at low QBER degradation of 0.93% and 1.1%
Operating penalties in single-fiber operation 10-Gb/s, 1024-way split, 110-km long-reach optical access networks
We report for the first time optical signal-to-noise
penalties which lead to performance degradations in single-fiber
long-reach optical access networks when compared to identical
dual-fiber systems. A simplified architecture, with reduced optical
amplifier count compared to previous work, for single-fiber operation
of a symmetrical 10-Gb/s, 1024-way split, 110-km long-reach
optical access network is presented and demonstrated. In addition,
a possible solution to remove the optical signal-to-noise penalty is
suggested
Coexistence of high-bit-rate quantum key distribution and data on optical fiber
Quantum key distribution (QKD) uniquely allows distribution of cryptographic
keys with security verified by quantum mechanical limits. Both protocol
execution and subsequent applications require the assistance of classical data
communication channels. While using separate fibers is one option, it is
economically more viable if data and quantum signals are simultaneously
transmitted through a single fiber. However, noise-photon contamination arising
from the intense data signal has severely restricted both the QKD distances and
secure key rates. Here, we exploit a novel temporal-filtering effect for
noise-photon rejection. This allows high-bit-rate QKD over fibers up to 90 km
in length and populated with error-free bidirectional Gb/s data communications.
With high-bit rate and range sufficient for important information
infrastructures, such as smart cities and 10 Gbit Ethernet, QKD is a
significant step closer towards wide-scale deployment in fiber networks.Comment: 7 pages, 5 figure
VCSEL-based, CWDM - PON systems using reflective technology for bi-directional multi-play service provision
Orthogonal frequency division multiplexing based on radio-overfiber schemes allows the direct use of multiple, native format wireless platforms. In combination with standard baseband provision such as Gigabit Ethernet, this provides access to a wide range of services without requiring specialized end-user equipment. However, such signals have a high laser power-bandwidth requirement which may not be a good fit to the domestic environment. Here we explore the use of low-power optical components in customer premises which interface with an intermediate optical network node. Two solutions in the context of SSMF over a CWDM optical network are described, based on either reflective or direct modulation. EVMs of better than 35 dB were achieved. ©2012 Optical Society of America
Quantum Metropolitan Optical Network based on Wavelength Division Multiplexing
Quantum Key Distribution (QKD) is maturing quickly. However, the current
approaches to its application in optical networks make it an expensive
technology. QKD networks deployed to date are designed as a collection of
point-to-point, dedicated QKD links where non-neighboring nodes communicate
using the trusted repeater paradigm. We propose a novel optical network model
in which QKD systems share the communication infrastructure by wavelength
multiplexing their quantum and classical signals. The routing is done using
optical components within a metropolitan area which allows for a dynamically
any-to-any communication scheme. Moreover, it resembles a commercial telecom
network, takes advantage of existing infrastructure and utilizes commercial
components, allowing for an easy, cost-effective and reliable deployment.Comment: 23 pages, 8 figure
QKD in Standard Optical Telecommunications Networks
To perform Quantum Key Distribution, the mastering of the extremely weak
signals carried by the quantum channel is required. Transporting these signals
without disturbance is customarily done by isolating the quantum channel from
any noise sources using a dedicated physical channel. However, to really profit
from this technology, a full integration with conventional network technologies
would be highly desirable. Trying to use single photon signals with others that
carry an average power many orders of magnitude bigger while sharing as much
infrastructure with a conventional network as possible brings obvious problems.
The purpose of the present paper is to report our efforts in researching the
limits of the integration of QKD in modern optical networks scenarios. We have
built a full metropolitan area network testbed comprising a backbone and an
access network. The emphasis is put in using as much as possible the same
industrial grade technology that is actually used in already installed
networks, in order to understand the throughput, limits and cost of deploying
QKD in a real network
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