Oral51 Videos

D01 – Non-Uniform Time-Stepping For Fast Simulation of Photodetectors Under High-Peak-Power, Ultra-Short Optical Pulses

Simsek E., Anjum I. Md, Carruthers T. F., Menyuk C. R.

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.

D02 – Electro-Optical Simulation and Characterization of DCR and secondary emission in SPADs

Novakovic B., Raymond K., Gallina G., Xie L., Retiere F., McGuire D.

We demonstrate the use of simulations in the modeling and characterization of important aspects of Single Photon Avalanche Detectors (SPADs). Electrically, we discuss the use of drift-diffusion and avalanche triggering probability solvers and results for dark count rate (DCR) and their comparison to measurements. Optically, we discuss the use of full wave electromagnetic solvers to […]

D03 – 3D multiphysics transient modeling of vertical Ge-on-Si pin waveguide photodetectors

Alasio M. G. C., Franco P., Tibaldi A., Bertazzi F., Namnabat S., Adams D., Gothoskar P., Masini G., Forghieri F., Ghione G., Goano M.

We report transient simulations of Ge-on-Si vertical pin waveguide photodetectors (WPDs), where the optical generation term used by the time-domain model is the FDTD solution of the electromagnetic problem treated as a spatially-distributed pulsed signal. This approach, validated against experimental measurements of the frequency response, paves the way to future studies of the dynamic response […]

IS01 – Network Authentication with Synchronized Chaotic Lasers

Lombardi L., Annovazzi-Lodi V., Aromataris G.

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 […]

IS02 – Exploring modern alternatives to the Whittaker-Shannon-Nyquist sampling theorem in THz Spectroscopy

Andersen C. D., Noura J. A. S., Mølvig B. H., Garcia O. G., Lange S. J.

We present simulations for a THz cross-correlation spectroscopy (THz-CCS) optical system. The aim is using compressed sensing (CS) to reconstruct the THz signal from a random under sampling of the signal and potentially replacing a delay stage unit of the THz-CCS system to increase robustness and cost-effectiveness of the optical system. We present results from […]

IS04 – All-optical AND Logic Gate Based on Semiconductor Optical Amplifiers for Implementing Deep Recurrent Neural Networks

Alam B., Ceschini A., Rosato A., Panella M., Asquini R.

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 […]

IS05 – Thermal crosstalk mitigation in a dual-drive Mach-Zehnder Modulator

De S., Das R., Singh K., Mandalawi Y., Kleine-Ostmann T., Schneider T.

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 […]

IS08 – Flat-band 8-Channel Optical MUX/DeMUX for Long Reach 400GbE Applications

Jeong S.-H.

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.

LD02 – Microscopic modeling of interface roughness scattering and application to the simulation of quantum cascade lasers

Grange T., Mukherjee S., Capellini G., Montanari M., Persichetti L., Di Gaspare L., Birner S., Attiaoui A., Moutanabbir O., Virgilio M., De Seta M.

The theory of interface roughness (IFR) scattering in semiconductor heterostructures is well established in the case of idealized abrupt interfaces. However, in reality, interfaces have a finite width, i.e. interfaces are graded. In such case, the effect of interface roughness, i.e. the breaking of in-plane invariance, a general framework has been lacking to describe the […]

LD04 – Modeling carrier transport in mid-infrared VCSELs with type-II superlattices and tunnel junctions

Torrelli V., Montoya J. A. G., Tibaldi A., Debernardi P., Simaz A., Belkin M. A., Goano M., Bertazzi F.

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 […]

LD05 – Data-Driven Modeling of Non-Markovian Noise in Semiconductor Lasers

Mertenskötter L., Kantner M.

Non-Markovian noise degrades the coherence properties of semiconductor lasers and contributes significantly to broadening of the linewidth. Since modeling of such colored noise systems from first principles is not accessible, we aim for a data-driven modeling approach in which a system of stochastic rate equations shall be reconstructed from time series data.

LD06 – Relative intensity noise of injection-locked epitaxial quantum dot laser on silicon

Chu Q., Zhao S., Grillot F., Wang J., He F., Zhang M., Xu X., Yao Y., Duan J.

This work investigates the relative intensity noise (RIN) characteristics of quantum dot (QD) lasers epitaxially grown on silicon subject to the optical injection. The effect of threading dislocation (TD), which acts as nonradiative recombination centers in the Shockley-Read-Hall (SRH) process, is considered in the rate equation model. The results reveal that the RIN is enhanced […]

LD07 – Physics-based time-domain modeling of VCSELs

D’Alessandro M., Gullino G., Tibaldi A., Bertazzi F., Goano M., Debernardi P.

This paper presents the results of a physics-based time-domain simulator for a vertical-cavity surface-emitting laser (VCSEL). We implemented a trapezoidal rule second order backward differentiation formula (TR-BDF2) to simulate the large signal response of the device under investigation, including the parasitic effects of the pin junction arising from an interplay of optical and carrier transport […]

LD08 – Modeling of THz Comb Emission in Difference-Frequency Quantum Cascade Lasers

Popp J., Seitner L., Schreiber M., Haider M., Consolino L., Cappelli F., De Natale P., Fujita K., Jirauschek C.

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 […]

LD10 – Effect of Self-Phase Modulation on The Signal Quality of Fourier Domain Mode-Locked Lasers

Aşırım O. E., Huber R., Jirauschek C.

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, […]

LED01 – First-principles computation of charge-carrier recombination coefficients in optoelectronic materials

Zhang X.

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 […]

LED02 – Carrier Transport in Multi Colour Deep Ultraviolet Light Emitting Diodes

Hofmann G., Höpfner J., Schilling M., Muhin A., Römer F., Wernicke T., Kneissl M., Witzigmann B.

Deep ultraviolet (DUV) light emitting diodes (LEDs) and lasers are enabled by high band gap Aluminium Gallium Nitride (AlGaN). The efficiency of recent multi quantum well (MQW) DUV emitters is still in the percent range which can be in part attributed to the hole injection. The hole injection and the carrier distribution in the high […]

LED04 – Development of time-dependent Exciton diffusion solver for modeling Triplet-Triplet Fusion Mechanism in OLEDs

Huang J.-Y., Hung H.-C., Hsu K.-C., Chen C.-H., Lee P.-H., Lin H.-Y., Lin B.-Y., Leung M.-K., Chiu T.-L., Lee J.-H., Wu Y.-R.

In this work, we developed a both stable and time-dependent exciton diffusion model including singlet and triplet exciton coupled with a modified Poisson & drift-diffusion solver to demonstrate the mechanism of triplet-triplet fusion (TTF) OLEDs. Using this modified simulator, we can demonstrate the characteristics of OLEDs including current-voltage curve, quantum efficiency performance, time-resolved electroluminescence spectrum, […]

LED05 – Reliable prediction of the singlet-triplet gap in TADF molecules with GW/BSE approach

Chaudhuri D., Patterson C. H.

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 […]

MM01 – Rigorous modal analysis of micro or nanoresonators

Lalanne P.

The most general motion of a system is a superposition of its normal modes, or eigenstates. We report our recent developments of a rigorous modal analysis of electromagnetic resonators, which is accurate even for geometries that have not been analyzed so far, e.g. 3D resonators made of dispersive media and placed in non-homogeneous backgrounds (on […]

MM02 – Carrier transport in (In,Ga)N quantum well systems: Connecting atomistic tight-binding electronic structure theory to drift-diffusion simulations

O’Donovan M., Farrell P., Streckenbach T., Koprucki T., Schulz S.

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 […]

MM03 – Implementation of Partially Reflecting Boundary Conditions in the Generalized Maxwell-Bloch Equations

Schreiber M., Popp J., Seitner L., Haider M., Jirauschek C.

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 […]

MM04 – Simulation of ac conductivity of monolayer MoS2 at terahertz frequencies

Mitra S.,

We present a multiphysics numerical tool for calculating the terahertz (THz) conductivity of transition-metal dichalcogenides (TMDs). The tool combines the ensemble Monte Carlo (EMC) technique for carrier transport with a three-dimensional finite-difference-time-domain (FDTD) solver for electromagnetic fields. We use the coupled EMC–FDTD technique to calculate the frequency-dependent conductivity in the terahertz range for monolayer MoS2, […]

MM05 – Comparison of flux discretizations for varying band edge energies

Moatti J., Farrell P.

Recently, a multiscale framework was developed where drift-diffusion is combined with atomistic tight-binding models. A naive flux discretization was proposed to tackle the problem of heavily fluctuating band edge energies which does not take into account mathematical complications. Here we would like to present several alternatives and compare them.