3,658 research outputs found
Electronic and photonic switching in the atm era
Broadband networks require high-capacity switches in order to properly manage large amounts of traffic fluxes. Electronic and photonic technologies are being used to achieve this objective both allowing different multiplexing and switching techniques. Focusing on the asynchronous transfer mode (ATM), the inherent different characteristics of electronics and photonics makes different architectures feasible. In this paper, different switching structures are described, several ATM switching architectures which have been recently implemented are presented and the implementation characteristics discussed. Three diverse points of view are given from the electronic research, the photonic research and the commercial switches. Although all the architectures where successfully tested, they should also follow different market requirements in order to be commercialised. The characteristics are presented and the architectures projected over them to evaluate their commercial capabilities.Peer ReviewedPostprint (published version
Controlling phonons and photons at the wavelength-scale: silicon photonics meets silicon phononics
Radio-frequency communication systems have long used bulk- and
surface-acoustic-wave devices supporting ultrasonic mechanical waves to
manipulate and sense signals. These devices have greatly improved our ability
to process microwaves by interfacing them to orders-of-magnitude slower and
lower loss mechanical fields. In parallel, long-distance communications have
been dominated by low-loss infrared optical photons. As electrical signal
processing and transmission approaches physical limits imposed by energy
dissipation, optical links are now being actively considered for mobile and
cloud technologies. Thus there is a strong driver for wavelength-scale
mechanical wave or "phononic" circuitry fabricated by scalable semiconductor
processes. With the advent of these circuits, new micro- and nanostructures
that combine electrical, optical and mechanical elements have emerged. In these
devices, such as optomechanical waveguides and resonators, optical photons and
gigahertz phonons are ideally matched to one another as both have wavelengths
on the order of micrometers. The development of phononic circuits has thus
emerged as a vibrant field of research pursued for optical signal processing
and sensing applications as well as emerging quantum technologies. In this
review, we discuss the key physics and figures of merit underpinning this
field. We also summarize the state of the art in nanoscale electro- and
optomechanical systems with a focus on scalable platforms such as silicon.
Finally, we give perspectives on what these new systems may bring and what
challenges they face in the coming years. In particular, we believe hybrid
electro- and optomechanical devices incorporating highly coherent and compact
mechanical elements on a chip have significant untapped potential for
electro-optic modulation, quantum microwave-to-optical photon conversion,
sensing and microwave signal processing.Comment: 26 pages, 5 figure
Efficient Guiding of Cold Atoms though a Photonic Band Gap Fiber
We demonstrate the first guiding of cold atoms through a 88 mm long piece of
photonic band gap fiber. The guiding potential is created by a far-off
resonance dipole trap propagating inside the fiber with a hollow core of 12 mu
m. We load the fiber from a dark spot 85-Rb magneto optical trap and observe a
peak flux of more than 10^5 atoms/s at a velocity of 1.5 m/s. With an
additional reservoir optical dipole trap, a constant atomic flux of 1.5 10^4
atoms/s is sustained for more than 150\,ms. These results open up interesting
possibilities to study nonlinear light-matter interaction in a nearly
one-dimensional geometry and pave the way for guided matter wave
interferometry.Comment: 8 pages, 3 figure
Quantum Modelling of Electro-Optic Modulators
Many components that are employed in quantum information and communication
systems are well known photonic devices encountered in standard optical fiber
communication systems, such as optical beamsplitters, waveguide couplers and
junctions, electro-optic modulators and optical fiber links. The use of these
photonic devices is becoming increasingly important especially in the context
of their possible integration either in a specifically designed system or in an
already deployed end-to-end fiber link. Whereas the behavior of these devices
is well known under the classical regime, in some cases their operation under
quantum conditions is less well understood. This paper reviews the salient
features of the quantum scattering theory describing both the operation of the
electro-optic phase and amplitude modulators in discrete and continuous-mode
formalisms. This subject is timely and of importance in light of the increasing
utilization of these devices in a variety of systems, including quantum key
distribution and single-photon wavepacket measurement and conformation. In
addition, the paper includes a tutorial development of the use of these models
in selected but yet important applications, such as single and multi-tone
modulation of photons, two-photon interference with phase-modulated light or
the description of amplitude modulation as a quantum operation.Comment: 29 pages, 10 figures, Laser and Photonics Reviews (in press
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