Perfectly matched layer (PML) boundary conditions have been used for several decades for the simulation of open domains within the finite difference time domain (FDTD) method. In this paper, we report on a new PML-based partially reflecting boundary condition for the generalized Maxwell-Bloch equations that enables setting a certain value of reflectance R at the […]
IS04 – All-optical AND Logic Gate Based on Semiconductor Optical Amplifiers for Implementing Deep Recurrent Neural Networks
The development of optical logic gates is a key factor for enabling next generation of computations in the context of Deep Learning and Quantum Computing. In this work, we introduce a scheme for the implementation of an all-optical AND logic gate, which makes use of semiconductor optical amplifiers (SOA) in cross-phase modulation configuration combined with […]
LED01 – First-principles computation of charge-carrier recombination coefficients in optoelectronic materials
Charge-carrier recombination plays a decisive role in determining the efficiency of optoelectronic materials and devices, but their accurate experimental measurements and interpretation are challenging. In this context, first-principles computation of charge-carrier recombination coefficients is particularly useful. It allows not only rigorous computation of the recombination rates, but also intuitive interpretation of the microscopic recombination mechanisms […]
NM03 – Simulation of Near-IR and Mid-IR Cascade Raman Microlasers Based on Bismuth-Modified Tungsten-Tellurite Glass
We theoretically investigate cascade Raman generation in bismuth-modified tungsten-tellurite glass microlasers, for the first time for microcavities based on TeO2 glasses. The calculated results demonstrate the opportunities of CW Raman generation in the near-IR and mid-IR ranges with CW pump at the wavelength of 1.55 μm. The predicted wavelengths are 1.81 µm, 2.17 µm, 2.70 […]
Organic light emitting diode (OLED) molecules that exhibit thermally activated delayed fluorescence (TADF) have emerged as a promising technology for various lighting and display applications. Such systems depend on low singlet-triplet gaps of the order of kT to allow reverse inter-system crossing. Here, we demonstrate the capability of a GW/BSE method to predict excitation energies […]
Directed Infrared Counter Measure (DIRCM) laser laboratory setups are used to mimic the real life DIRCM system and IR heat-seeking missile engagement scenarios in isolated laboratory environments. Typically, the output beam of a mid-infrared (Mid-IR) laser source is modulated in time using an acousto-optic (AO) modulator (AOM). Following the AOM in the optical path, within […]
In this paper, the impact of self-phase modulation on the noise performance of Fourier Domain Mode-Locked (FDML) lasers is investigated. It is shown that under a relatively high fiber nonlinearity and/or intracavity signal amplitude, an excess amount of noise generation occurs, which can not only lead to poor signal quality, but also operational instability. Hence, […]
LD04 – Modeling carrier transport in mid-infrared VCSELs with type-II superlattices and tunnel junctions
Vertical-cavity surface-emitting lasers are promising light sources for sensing and spectroscopy applications in the midinfrared 3 ÷4 µm spectral region. A type-II superlattice active region is used for carrier injection and confinement, while a buried tunnel junction defines a current aperture, decreasing the series resistivity. Highly nanostructured to optimize device performance, mid-infrared VCSELs pose modeling […]
A semi-analytic approach for modelling the distributed capacitance and the elecro-optic confinement factor of the slot waveguide in a silicon-organic hybrid Mach-Zehnder modulator using the principle of conformal mapping is presented. The results show a deviation of less than 1.3% compared with numerical field simulations.
D01 – Non-Uniform Time-Stepping For Fast Simulation of Photodetectors Under High-Peak-Power, Ultra-Short Optical Pulses
A novel non-uniform time-stepping procedure is developed to reduce the memory usage and simulation time—by two orders of magnitude—of photodetectors when detecting high-peak-power, ultra-short optical pulses. The proposed procedure can be used in other marching-on-in-time solvers to achieve the same for the simulations dealing with ultra-short pulses.
MM02 – Carrier transport in (In,Ga)N quantum well systems: Connecting atomistic tight-binding electronic structure theory to drift-diffusion simulations
Understanding the impact of the alloy microstructure on carrier transport in (In,Ga)N/GaN quantum well systems is important for aiding device design. We study the impact that alloy fluctuations have on uni-polar carrier transport for both electrons (n-i-n junction) and holes (p-i-p junction) using a multiscale framework. To do so we connect an atomistic tight-binding model […]
The generation of terahertz (THz) frequency comb emission by intracavity difference frequency generation (DFG) in a mid-infrared (mid-IR) quantum cascade laser (QCL) is a promising alternative to direct THz QCL frequency comb generation. Concerning their room temperature operation capabilities, these devices are well suited for applications in rotational molecular spectroscopy and sensing. In order to […]
D05 – Mode-Guided Infrared Absorption in Ge/SiO2 Grating for Large-Angle and Broadband Photodetection
The numerical simulation of the electromagnetic properties of the Ge/SiO2 grating structure with bottom distributed Bragg reflector. With mode guiding in Ge, the structure exhibits an absorption angle of 100° and broadband behavior from 1300 to 1500 nm.
We numerically study a hardware method for network authentication, where a pair of matched (twins) chaotic lasers generate the same chaos when they synchronize, being subject to the same optical injection from a third chaotic laser. One of the lasers is in the secure environment, the other in the unsecure environment, and authorization is granted […]
Due to its flexibility, perovskite materials are a promising candidate for many semiconductor devices. For example, Perovskite Solar Cells (PSCs) have become recently one of the fastest growing photovoltaic technologies. In this work, we take volume exclusion effects into account by formulating two different current densities – either treating the mobility or the diffusion as […]
N02 – Influence of random alloy fluctuations on the electronic properties of axial In(x)Ga(1−x)N/GaN nanowire heterostructures
Compound semiconductor heterostructures such as quantum dots, nanowires, or thin films, are commonly subject to randomly fluctuating alloy compositions if they contain ternary and quaternary alloys. These effects are obviously of an atomistic nature and thus rarely considered in heterostructure designs that require simulations on a continuum level for theory-guided design or interpretation of observations. […]
NM05 – Modeling the Effects of Surface Recombination Velocity in Scanning Photocurrent Microscopy for Ohmic-Contact Thin-Film Devices
We studied numerically the carrier transport and confirmed the feasibility of our scanning photocurrent microscopy model in the minority carrier decay length extraction under different surface recombination velocities at the surfaces of ohmic-contact thin-film devices.
A quantum key distribution system –employing a key time-bin qubit and a security-pass polarization-randomized qubit– is shown to overcome a wide class of intercept-resend attacks adopting the use of faked-state light; including attacks based on blinding of single-photon avalanche detectors (SPADs).
We propose novel optical demultiplexer scheme for LR-8 applications, and theoretically verify flatband spectral response with the discrete 8-channel wavelengths. By the additional band rejection filter, non-continuous wavelength filtering response was achieved with spectral flatness and low crosstalk of < -15dB within an entire LR-8 targeted spectral range.
Dual-drive, PIN-diode based Mach-Zehnder modulators are pivotal for power-efficient and cost-effective CMOS compatible optical transceivers with small footprints. However, the basic chip materials have substantial thermal conductance resulting in thermal crosstalk, which eventually deteriorates the modulator performance in terms of bandwidth and data transmission capabilities. In this work, we simulate and analyze the influence of […]
A novel full-vectorial meshfree finite cloud mode solver is proposed for analysis of fused optic-fiber couplers, in which the curvilinear coordinate mapping technique is used to map a cloud with curved interface onto a unit square. Numerical results are compared with prior analysis using the finite difference method, showing the validity and utility of the […]