537 research outputs found
Diamond Integrated Optomechanical Circuits
Diamond offers unique material advantages for the realization of micro- and
nanomechanical resonators due to its high Young's modulus, compatibility with
harsh environments and superior thermal properties. At the same time, the wide
electronic bandgap of 5.45eV makes diamond a suitable material for integrated
optics because of broadband transparency and the absence of free-carrier
absorption commonly encountered in silicon photonics. Here we take advantage of
both to engineer full-scale optomechanical circuits in diamond thin films. We
show that polycrystalline diamond films fabricated by chemical vapour
deposition provide a convenient waferscale substrate for the realization of
high quality nanophotonic devices. Using free-standing nanomechanical
resonators embedded in on-chip Mach-Zehnder interferometers, we demonstrate
efficient optomechanical transduction via gradient optical forces. Fabricated
diamond resonators reproducibly show high mechanical quality factors up to
11,200. Our low cost, wideband, carrier-free photonic circuits hold promise for
all-optical sensing and optomechanical signal processing at ultra-high
frequencies
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
Design and simulation of high-speed nanophotonic electro-optic modulators
In this work, an ultracompact electro-optic modulator based on refractive index modulation by plasma dispersion effect in PhC all-optical gate (AOG) is proposed. The index modulation is achieved by applying a time-varying bias voltage across the electrical contacts of the AOG. The proposed modulator has potential for high-speed operation, with bandwidths in excess of 30GHz achievable
Impact of slow-light enhancement on optical propagation in active semiconductor photonic crystal waveguides
We derive and validate a set of coupled Bloch wave equations for analyzing
the reflection and transmission properties of active semiconductor photonic
crystal waveguides. In such devices, slow-light propagation can be used to
enhance the material gain per unit length, enabling, for example, the
realization of short optical amplifiers compatible with photonic integration.
The coupled wave analysis is compared to numerical approaches based on the
Fourier modal method and a frequency domain finite element technique. The
presence of material gain leads to the build-up of a backscattered field, which
is interpreted as distributed feedback effects or reflection at passive-active
interfaces, depending on the approach taken. For very large material gain
values, the band structure of the waveguide is perturbed, and deviations from
the simple coupled Bloch wave model are found.Comment: 8 pages, 5 figure
Benchmarking five numerical simulation techniques for computing resonance wavelengths and quality factors in photonic crystal membrane line defect cavities
We present numerical studies of two photonic crystal membrane microcavities,
a short line-defect cavity with relatively low quality () factor and a
longer cavity with high . We use five state-of-the-art numerical simulation
techniques to compute the cavity factor and the resonance wavelength
for the fundamental cavity mode in both structures. For each method,
the relevant computational parameters are systematically varied to estimate the
computational uncertainty. We show that some methods are more suitable than
others for treating these challenging geometries.Comment: Revised and final version for publication. 28 pages, 10 figures, 7
table
Photonic Applications Based on Bimodal Interferometry in Periodic Integrated Waveguides
Tesis por compendio[ES] La fotónica de silicio es una tecnología emergente clave en redes de comunicación e
interconexiones de centros de datos de nueva generación, entre otros. Su éxito se basa
en la utilización de plataformas compatibles con la tecnología CMOS para la integración
de circuitos ópticos en dispositivos pequeños para una producción a gran escala a
bajo coste. Dentro de este campo, los interferómetros integrados juegan un papel
crucial en el desarrollo de diversas aplicaciones fotónicas en un chip como sensores
biológicos, moduladores electro-ópticos, conmutadores totalmente ópticos, circuitos
programables o sistemas LiDAR, entre otros. Sin embargo, es bien sabido que la
interferometría óptica suele requerir caminos de interacción muy largos, lo que dificulta
su integración en espacios muy compactos. Para mitigar algunas de estas limitaciones de
tamaño, surgieron varios enfoques, incluyendo materiales sofisticados o estructuras más
complejas, que, en principio, redujeron el área de diseño pero a expensas de aumentar
los pasos del proceso de fabricación y el coste.
Esta tesis tiene como objetivo proporcionar soluciones generales al problema de
tamaño típico de los interferómetros ópticos integrados, con el fin de permitir la
integración densa de dispositivos basados en silicio. Para ello, aunamos los beneficios
tanto de las guías de onda bimodales como de las estructuras periódicas, en términos
de la mejora del rendimiento y la posibilidad para diseñar interferómetros monocanal
en áreas muy reducidas. Más específicamente, investigamos los efectos dispersivos
que aparecen en estructuras menores a la longitud de onda y en las de cristal fotónico,
para su implementación en diferentes configuraciones interferométricas bimodales.
Además, demostramos varias aplicaciones potenciales como sensores, moduladores y
conmutadores en tamaños ultra compactos de unas pocas micras cuadradas. En general,
esta tesis propone un nuevo concepto de interferómetro integrado que aborda los
requisitos de tamaño de la fotónica actual y abre nuevas vías para futuros dispositivos
basados en funcionamiento bimodal.[CA] La fotònica de silici és una tecnologia emergent clau en xarxes de comunicació i
interconnexions de centres de dades de nova generació, entre altres. El seu èxit es basa
en la utilització de plataformes compatibles amb la tecnologia CMOS per a la integració
de circuits òptics en dispositius diminuts per a una producció a gran escala a baix
cost. Dins d'aquest camp, els interferòmetres integrats juguen un paper crucial en el
desenvolupament de diverses aplicacions fotòniques en un xip com a sensors biològics,
moduladors electro-òptics, commutadors totalment òptics, circuits programables o
sistemes LiDAR, entre altres. No obstant això, és ben sabut que la interferometría òptica
sol requerir camins d'interacció molt llargs, la qual cosa dificulta la seua integració en
espais molt compactes. Per a mitigar algunes d'aquestes limitacions de grandària, van
sorgir diversos enfocaments, incloent materials sofisticats o estructures més complexes,
que, en principi, van reduir l'àrea de disseny però a costa d'augmentar els processos de
fabricació i el cost.
Aquesta tesi té com a objectiu proporcionar solucions generals al problema de
grandària típica dels interferòmetres òptics integrats, amb la finalitat de permetre la
integració densa de dispositius basats en silici. Per a això, combinem els beneficis tant de
les guies d'ones bimodals com de les estructures periòdiques, en termes de funcionament
d'alt rendiment per a dissenyar interferòmetres monocanal compactes en àrees molt
reduïdes. Més específicament, investiguem els efectes dispersius que apareixen en
estructures menors a la longitud d'ona i en les de cristall fotònic, per a la seua
implementació en diferents configuracions interferomètriques bimodals. A més, vam
demostrar diverses aplicacions potencials com a sensors, moduladors i commutadors en
grandàries ultres compactes d'unes poques micres cuadrades. En general, aquesta tesi
proposa un nou concepte d'interferòmetre integrat que aborda els requisits de grandària
de la fotònica actual i obri noves vies per a futurs dispositius basats en funcionament
bimodal.[EN] Silicon photonics is a key emerging technology in next-generation communication
networks and data centers interconnects, among others. Its success relies on the
ability of using CMOS-compatible platforms for the integration of optical circuits
into small devices for a large-scale production at low-cost. Within this field,
integrated interferometers play a crucial role in the development of several on-chip
photonic applications such as biological sensors, electro-optic modulators, all-optical
switches, programmable circuits or LiDAR systems, among others. However, it is well
known that optical interferometry usually requires very long interaction paths, which
hinders its integration in highly compact footprints. To mitigate some of these size
limitations, several approaches emerged including sophisticated materials or more
complex structures, which, in principle, reduced the design area but at the expense of
increasing fabrication process steps and cost.
This thesis aims at providing general solutions to the long-standing size problem
typical of optical integrated interferometers, in order to enable the densely integration
of silicon-based devices. To this end, we combine the benefits from both bimodal
waveguides and periodic structures, in terms of high-performance operation and
compactness to design single-channel interferometers in very reduced areas. More
specifically, we investigate the dispersive effects that arise from subwavelength
grating and photonic crystal structures for their implementation in different bimodal
interferometric configurations. Furthermore, we demonstrate various potential
applications such as sensors, modulators and switches in ultra-compact footprints of
a few square microns. In general, this thesis proposes a new concept of integrated
interferometer that addresses the size requirements of current photonics and open up
new avenues for future bimodal-operation-based devices.Financial support is also gratefully acknowledged through postdoctoral FPI grants from Universitat Politècnica de València (PAID-01-18). European Commission through the Horizon 2020 Programme (PHC-634013 PHOCNOSIS project).
The authors acknowledge funding from the Generalitat Valenciana through the AVANTI/2019/123, ACIF/2019/009 and PPC/2020/037 grants and from the European
Union through the operational program of the European Regional Development Fund (FEDER) of the Valencia Regional Government 2014–2020.Torrijos Morán, L. (2021). Photonic Applications Based on Bimodal Interferometry in Periodic Integrated Waveguides [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/172163TESISCompendi
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