119,083 research outputs found
Advanced finite-element methods for design and analysis of nanooptical structures: Applications
An overview on recent applications of the finite-element method
Maxwell-solver JCMsuite to simulation tasks in nanooptics is given. Numerical
achievements in the fields of optical metamaterials, plasmonics, photonic
crystal fibers, light emitting devices, solar cells, optical lithography,
optical metrology, integrated optics, and photonic crystals are summarized
Theory and simulation of quantum photovoltaic devices based on the non-equilibrium Green's function formalism
This article reviews the application of the non-equilibrium Green's function
formalism to the simulation of novel photovoltaic devices utilizing quantum
confinement effects in low dimensional absorber structures. It covers
well-known aspects of the fundamental NEGF theory for a system of interacting
electrons, photons and phonons with relevance for the simulation of
optoelectronic devices and introduces at the same time new approaches to the
theoretical description of the elementary processes of photovoltaic device
operation, such as photogeneration via coherent excitonic absorption,
phonon-mediated indirect optical transitions or non-radiative recombination via
defect states. While the description of the theoretical framework is kept as
general as possible, two specific prototypical quantum photovoltaic devices, a
single quantum well photodiode and a silicon-oxide based superlattice absorber,
are used to illustrated the kind of unique insight that numerical simulations
based on the theory are able to provide.Comment: 20 pages, 10 figures; invited review pape
Semiconductor Optical Amplifier for Next Generation of High Data Rate Optical Packet-Switched Networks
This chapter provides an overview of considerations for the development of semiconductor optical amplifiers (SOA) for the next generations of packet-switched optical networks. SOA devices are suitable candidates in order to realize high-performance optical gates due to their high extinction ratio and fast switching time. However such devices also introduce linear and nonlinear noise. The impact of SOA devices on several modulation formats via theoretical model, numerical simulation, and experimental validation is studied. Impairments introduced by SOAs are considered in order to derive some general network design rules
Phenomenological modeling of Geometric Metasurfaces
Metasurfaces, with their superior capability in manipulating the optical
wavefront at the subwavelength scale and low manufacturing complexity, have
shown great potential for planar photonics and novel optical devices. However,
vector field simulation of metasurfaces is so far limited to
periodic-structured metasurfaces containing a small number of meta-atoms in the
unit cell by using full-wave numerical methods. Here, we propose a general
phenomenological method to analytically model metasurfaces made up of
arbitrarily distributed meta-atoms based on the assumption that the meta-atoms
possess localized resonances with Lorentz-Drude forms, whose exact form can be
retrieved from the full wave simulation of a single element. Applied to phase
modulated geometric metasurfaces, our analytical results show good agreement
with full-wave numerical simulations. The proposed theory provides an efficient
method to model and design optical devices based on metasurfaces.Comment: 16 pages, 8 figure
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WIAS-TeSCA - Two-dimensional semi-conductor analysis package
WIAS-TeSCA (Two- and three-dimensional semiconductor analysis package) is a simulation
tool for the numerical simulation of charge transfer processes in semiconductor
structures, especially in semiconductor lasers. It is based on the drift-diffusion model and
considers a multitude of additional physical effects, like optical radiation, temperature influences
and the kinetics of deep impurities. Its efficiency is based on the analytic study of
the strongly nonlinear system of partial differential equations – the van Roosbroeck system
– which describes the electron and hole currents. Very efficient numerical procedures for
both the stationary and transient simulation have been implemented.
WIAS-TeSCA has been successfully used in the research and industrial development of
new electronic and optoelectronic semiconductor devices such as transistors, diodes, sensors,
detectors and lasers and has already proved its worth many times in the planning
and optimization of these devices. It covers a broad spectrum of applications, from heterobipolar
transistor (mobile telephone systems, computer networks) through high-voltage
transistors (power electronics) and semiconductor laser diodes (fiber optic communication
systems, medical technology) to radiation detectors (space research, high energy physics).
WIAS-TeSCA is an efficient simulation tool for analyzing and designing modern semiconductor
devices with a broad range of performance that has proved successful in solving
many practical problems. Particularly, it offers the possibility to calculate self-consistently
the interplay of electronic, optical and thermic effects
Hybrid quantum-classical modeling of quantum dot devices
The design of electrically driven quantum dot devices for quantum optical
applications asks for modeling approaches combining classical device physics
with quantum mechanics. We connect the well-established fields of
semi-classical semiconductor transport theory and the theory of open quantum
systems to meet this requirement. By coupling the van Roosbroeck system with a
quantum master equation in Lindblad form, we introduce a new hybrid
quantum-classical modeling approach, which provides a comprehensive description
of quantum dot devices on multiple scales: It enables the calculation of
quantum optical figures of merit and the spatially resolved simulation of the
current flow in realistic semiconductor device geometries in a unified way. We
construct the interface between both theories in such a way, that the resulting
hybrid system obeys the fundamental axioms of (non-)equilibrium thermodynamics.
We show that our approach guarantees the conservation of charge, consistency
with the thermodynamic equilibrium and the second law of thermodynamics. The
feasibility of the approach is demonstrated by numerical simulations of an
electrically driven single-photon source based on a single quantum dot in the
stationary and transient operation regime
Multi-dimensional modeling and simulation of semiconductor nanophotonic devices
Self-consistent modeling and multi-dimensional simulation of semiconductor nanophotonic devices is an important tool in the development of future integrated light sources and quantum devices. Simulations can guide important technological decisions by revealing performance bottlenecks in new device concepts, contribute to their understanding and help to theoretically explore their optimization potential. The efficient implementation of multi-dimensional numerical simulations for computer-aided design tasks requires sophisticated numerical methods and modeling techniques. We review recent advances in device-scale modeling of quantum dot based single-photon sources and laser diodes by self-consistently coupling the optical Maxwell equations with semiclassical carrier transport models using semi-classical and fully quantum mechanical descriptions of the optically active region, respectively. For the simulation of realistic devices with complex, multi-dimensional geometries, we have developed a novel hp-adaptive finite element approach for the optical Maxwell equations, using mixed meshes adapted to the multi-scale properties of the photonic structures. For electrically driven devices, we introduced novel discretization and parameter-embedding techniques to solve the drift-diffusion system for strongly degenerate semiconductors at cryogenic temperature. Our methodical advances are demonstrated on various applications, including vertical-cavity surface-emitting lasers, grating couplers and single-photon sources
Numerical simulation and design of semiconductor quantum dot-based lasers and amplifiers
Numerical simulation and design of semiconductor quantum dot-based lasers and amplifier
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