arXiv subjects

Hassan Kaatuzian

Publications and source records attributed to Hassan Kaatuzian.

16 recordsLinked to original sources

arXiv2025

A Survey on Continuous Variable Quantum Key Distribution for Secure Data Transmission: Toward the Future of Secured Quantum-Networks

Quantum key distribution (QKD) represents a cornerstone of secure communication in the quantum era. While discrete-variable QKD (DV-QKD) protocols were historically the first to demonstrate secure key exchange, continuous-variable QKD (CV-QKD) has emerged as a more practical alternative due to its seamless compatibility with current telecommunications infrastructure. CV-QKD relies on coherent and squeezed states of light, offering significant advantages for integration into modern optical networks. This review comprehensively explores the theoretical underpinnings, technological advancements, and practical challenges of CV-QKD. Special attention is given to the role of photonic integrated circuits (PICs) in enabling scalable and efficient implementation of CV-QKD systems. Furthermore, recent advances in machine learning have been leveraged to optimize CV-QKD performance, with data-driven techniques enhancing noise estimation, parameter optimization, and system security. Additionally, tensor networks provide efficient computational tools for analyzing complex quantum correlations, improving the efficiency and robustness of quantum key distribution protocols. These developments, combined with ongoing improvements in quantum photonic integration, pave the way for the practical deployment of large-scale, high-speed quantum-secure networks.

quant-ph↗

arXiv2020

Large signal analysis of multiple quantum well transistor lasers: Investigation of imbalanced carrier and photon density distribution

In this paper, we present a large signal and switching analysis for the Heterojunction Bipolar Transistor Laser (TL) to reveal its optical and electrical behavior under high current injection conditions. Utilizing appropriate models for carrier transport, nonlinear optical gain and optical confinement factor (OCF), we have simulated the large signal response of the HBTL in relatively low and high modulation frequencies. Our results predict that for multiple quantum well structures at low frequencies there should not be a difference in carrier density either the photon density. However, carrier concentration can be differently distributed between subsequent wells in case of a high speed yet large signal input. This leads to increased linewidth instead as it depends on ΔNqw. We show the effect of different structural parameters on the switching behavior by performing a switching analysis of the Single Quantum Well (SQW) and Multiple Quantum Well (MQW) structures using computationally efficient numerical methods. A set of coupled rate equations is solved to investigate the large-signal and switching behavior of MQW-HBTL. Finally, to have a comprehensive judgment about this optoelectronic device, we introduce a relative performance factor to taking into account all the optoelectronic characteristics such as output power, ac current gain, modulation bandwidth, and base threshold current as well as turn-on time in order to design a suitable TL for Opto-Electronic Integrated Circuits (OEICs).

physics.app-ph↗

arXiv2019

Quantum Photonic Estimation of Refractive Index in 2-methyl-4-nitroaniline ElectroOptic Crystal

In this paper, we will try to explain the method of theoretical estimation of index of refraction of an assymetric organic Electro-Optic compound called MNA or 2,methyl,4,nitro-aniline. It is transparent in a wide range between 500nm-2000nm wavelengths. We assume a Quantum Photonic Model which is based on Bohmian Mechanics for Electron-Photon interactions. The photons interact with pi-electrons of MNA molecules, when they pass in the atomic layers. During this electron-photon interaction the photon is temporarily annihilated and all of its energy will be delivered into electron in orbit as kinetic energy in every layer. After a short while the photon will be recreated. With reasonable and precise calculations of these delays we may estimate theoretically Ordinary and Extraordinary refractive indices of MNA compound. Quarter wave thickness for MNA crystal has also been estimated according to phase retardation simulations. Attained results from this Quantum Photonic model - Montecarlo time domain method, is estimated to be very close to experimental quantities with errors always less than 6 percents.

cond-mat.mes-hall↗

arXiv2019

Analysis and design of a Germanium multi-quantum well metal strip nanocavity plasmon laser

In order to achieve electrically pumped plasmon nano lasers, several structures, materials and methods, have been proposed recently. However, there is still a long way to find out a reliable appropriate on-chip plasmon source for commercial plasmonic integrated circuits. In this paper, a new waveguide integrated nanocavity plasmon laser is proposed for 1550 nm free-space wavelength. Due to its significant field confinement resulted by the metal strip structure and strong interaction of plasmonic modes with the germanium quantum wells and as a result a considerable Purcell factor about 291, this structure has a remarkable output performance. Using semi-classical rate equations in combination with finite difference time domain (FDTD) cavity mode analysis, the output performance measures are estimated and confirmed with respect to various physical models and simulation tools. Simulation results for this tiny structure (0.073 um2 area) show a 2.8uW output power with 10uA injection current and about 4.16mW output power with the threshold pump current of 27mA while maintaining its performance in a wide modulation bandwidth of 178GHz.

physics.app-ph↗

arXiv2019

Hydrodynamic Analysis and Responsivity improvement of a metal/semiconductor/metal plasmonic detector

Characteristics improvement of photon/plasmon detectors have been the subject of several investigations in the area of plasmonic integrated circuits. Among different suggestions, Silicon-based Metal-Semiconductor-Metal (MSM) waveguides are one of the most popular structures for implementation of high-quality photon/plasmon detectors in infrared wavelengths. In this paper, an integrated Silicon Germanium (SiGe) core MSM plasmon detector is proposed to detect lambda=1550 nm with internal photoemission mechanism. Performance characteristics of the new device are simulated with a simplified hydrodynamic model. In a specific bias point (V=3 V and the incident optical power of 0.31 mW), the output current is 404.3 uA (276 uA detection current and 128.3 uA dark current), responsivity is 0.89 A/W and the 3-dB electrical bandwidth is 120 GHz. Simulation results for the proposed Plasmon detector, in comparison with the empirical results of a reported Si-based MSM device, demonstrate considerable responsivity enhancement.

physics.app-ph↗

arXiv2018

Design and Analysis of a multiple quantum-well plasmonic Germanium/Silicon-Germanium nanolaser

There are many researches reported in using Germanium in Silicon based lasers but acquiring this potential for a nanolaser may also be important for development of a CMOS compatible plasmon source. In this paper, a Ge/SiGe multiple quantum well waveguide integrated nanolaser is introduced and theoretically investigated. This structure is simulated and by means of a semi-classical rate equation model, its performance is studied. The proposed nano laser has a tiny footprint of 0.07um^2, room temperature performance and CMOS compatible fabrication process. The output performance of the proposed structure as estimated, is noticeable. These simulated results, compared with some experiments and redundant software double checking, show acceptable compatibility. In 1550nm output wavelength, it provides 3.83uW output power with 1uA injection current while maintaining its performance in a wide modulation bandwidth of 24.5GHz. This remarkable performance is achieved thanked to a Purcell factor equal to 2208.

physics.optics↗

arXiv2018

Design and simulation of a low dark current metal/silicon/metal integrated plasmonic detector

Silicon-based waveguide plasmon detectors have a great research interest because of CMOS compatibility and integration capability with other plasmonic integrated circuits. In this paper, a balanced metal-semiconductor-metal (MSM) integrated plasmonic detector is proposed to isolate the output from dark current and made it suitable for low noise applications. Performance characteristics of the new device are numerically simulated. In a specific bias point (V = 3 V), the output current is estimated to be about 31.8 μA and responsivity is 0.1288 A/W for a device with 2 μm2 area. Simulation results for this balanced Plasmon detector demonstrate considerable dark current reduction compared with unbalanced plasmon detectors. Our estimated theoretical I-V characteristic, fits appropriately with experimental curve results reported before.

physics.app-ph↗

arXiv2018

Semi-Classical Analysis and Design of Quantum dot Based Electrically Pumped plasmonic nanolaser

Recently there is an increasing attention to electrically pumped room temperature sub-wavelength plasmon sources because of their various potential applications mainly in the integrated plasmonic field. In this paper, a GaAs/AlGaAs quantum dot based waveguide integrated plasmonic nanolaser is introduced and theoretically investigated. Using a semi-classical rate equation model, performance of our nanolaser is studied and its characteristics are presented in details. The proposed nanolaser has a tiny footprint of 0.25 um2, room temperature operating condition and CMOS friendly process while having remarkable output performance. The new structure generates 1uW output power with 3.5mA injection current ( the threshold pump current is calculated to be about 2.5uA ) in 850 nm and has wide modulation frequency of 10 THz in threshold pumping rate, large Purcell factor about 3460 and high output coupling ratio to the host plasmonic waveguide.

physics.optics↗

arXiv2018

Analysis and design of a SiGe-HBT based terahertz detector for imaging arrays applications

In this paper, we will introduce a new designed direct conversion terahertz detector and we will compare its characteristics with a prefabricated design in order to obtain better performance of our new proposed design. Differences between our new work and prefabricated device are in both physical structure by introducing an exponentially graded base SiGe-HBT instead of linearly graded ones, and configuration of components by means of merging two transistor of the initial common base structure into a single transistor with two base contacts, which equivalent to two transistors in common emitter configuration. New proposed detector, at first will be analyzed with a compact circuit model and then for more accurate analysis, two dimensional carrier transport analysis will be performed with numerical methods. Comparison of new and prefabricated detector will be done by simulation of both new and prefabricated devices with the same simulator. Because of only a slight change in transistor physical structure, if our simulation results and previous empirical data have a good matching for prefabricated device then with a high degree of precision we can claim our comparison is verified, but of course, for better confirmation of our ideas, fabrication and experimental measurements should be done in the next steps. Responsivity and minimum noise equivalent power of new detector are about 4.9A/W and 6.5pW/Hz1/2 respectively, while these characteristics for prefabricated detector, are about 1A/W and 50pW/Hz1/2 respectively. Also about 231uW/pixel decrement in power consumption for the same responsivity, and a same bandwidth have been achieved.

physics.app-ph↗

arXiv2016

Graded index SCH transistor laser: Analysis of various confinement structures

New configuration of confinement structure is utilized to improve optoelectronic performances, including threshold current, AC current gain as well as optical bandwidth and optical output power of single quantum well transistor laser. Considering the drift component in addition to the diffusion term in electron current density, a new continuity equation is developed to analyze the proposed structures. Physical parameters including, electron mobility, recombination lifetime, optical confinement factor, electron capture time and photon lifetime is calculated for new structures. Based on solving continuity equation in separate confinement heterostructures, threshold current reduces 67% and optical output power increases 37%.

cond-mat.mes-hall↗

arXiv2012

Bandwidth enhancement and optical performances of multiple quantum well transistor lasers

A detailed rate-equation-based model is developed to study carrier transport effects on optical and electrical characteristics of the Multiple Quantum Well Heterojunction Bipolar Transistor Laser in time-domain. Simulation results extracted using numerical techniques in small-signal regime predict significant enhancement in device optical bandwidth when multiple quantum wells are used. Cavity length and base width are also modified to optimize the optoelectronic performances of the device. An optical bandwidth of \approx 60GHz is achieved in the case of 5 quantum wells each of 70A widths and a cavity length of 200um.

physics.optics↗

arXiv2007

Electro-Optic Effect Explanation with Quantum Photonic Model

In this paper, we have explained transverse electro-optic effect by quantum-photonic model (QPM). This model interpret this effect by photon-electron interaction in attosecond regime. We simulate applied electric field on molecule and crystal by Monte-Carlo method in time domain when a light beam is propagated through the waveguide. We show how the waveguide response to an optical signal with different wavelengths when a transverse electric field applied to the waveguide.

quant-ph↗

arXiv2007

Analysis and Design of an Organic High Speed Digital Electro-Optic Switch

We have analyzed and designed an organic high speed digital optical switch (DOS) based on transverse electro-optic effect. In analysis section, we proposed a quantum photonic model (QPM) to explain linear electro-optic (EO) effect. This model interpret this effect by photon-electron interaction in attosecond regime. We simulate applied electric field on molecule and crystal by Monte-Carlo method in time domain. We show how a waveguide response to an optical signal with different wavelengths when a transverse electric field applied to the waveguide. In design section, we configure conceptually a 2 * 2 EO switch with full adiabatic coupler. In this DOS, we use a rib waveguides that its core has been constructed from NPP crystal. This switch is smaller at least to one-half of similar DOS in dimensions.

quant-ph↗

arXiv2006

A Nano-Quantum Photonic Model for Justification of Dispersion in Single Crystal Film of NPP

In this paper, we present a nano-quantum photonic model for justification of normal dispersion in a thin crystal film of NPP. In this method, we assume a laser beam consists of a flow of energetic particles. By precise analyzing of photon interaction with pi-electron system of benzene ring in NPP crystal, we will attain refractive index (RI) in any wavelength and compare the results with experimental data.

quant-ph↗

arXiv2005

Electromagnetically Induced Transparency using six level atoms doped in the crystalline medium

Using the density matrix theory of interaction between light and matter, and relevant parameters of the relaxation rates for a six-level model, we have shown theoretically the possibility of realizing Electromagnetically Induced Transparency (EIT) and Slow Light effects in Pr(+3 ion) doped YSO crystal. In addition, we have presented a simplified method to analyse EIT effect in such a six level atomic system. Finally, we have demonstrated results of numerical calculation and have compared them with experimental measurements reported recently.

quant-ph↗

arXiv2005

Analysis of Quantum Light Memory in Atomic Systems (Final)

We extend the theory of quantum light memory in atomic ensemble of Lambda type atoms with considering lower levels coherence decay rate and one and two-photon detunings from resonances in low intensity and adiabatic passage limit. We obtain that with considering these parameters, that there will be a considerable decay of probe pulse and stored information; also, we obtain that the group velocity of probe (light) pulse and its amplitude does not tend to zero by turning off the control field. We propose a method to keep the probe pulse in small values in turn off time of control field and to reduce the loss of the stored probe pulse. In addition, we obtain that in the Off-resonance case there will be a considerable distortion of the output light pulse that causes in loss of the stored information, then we present limitations for detunings and therefore for bandwidths of practical lasers also limitations for maximum storage time to have negligible distortion of stored information. We finally present the numerical calculations and compare them with analytical results.

quant-ph↗