Performance enhancement of an ultrafast graphene photodetector via simultaneous two-mode absorption in a hybrid plasmonic waveguide.

An ultrafast, compact, zero-biased, and complementary metal-oxide semiconductor-compatible graphene photodetector (PD) based on a silicon-on-insulator hybrid plasmonic waveguide (HPWG) is proposed. Lumerical MODE solver is employed to investigate the modal characteristics of TM-polarized modes in the HPWG composing the PD. It is shown that the input light can be completely coupled into the photonic-like and plasmonic-like fundamental TM modes at the PD section.

Efficiency analysis of cellular/LiFi traffic offloading.

Data offloading is a promising low-cost and power-efficient solution for the expected high demands for high-speed connectivity in the near future. We investigate offloading efficiency in a cellular/light fidelity (LiFi) network. This offloading efficiency is a measure of the ratio of traffic carried by the LiFi network to the total traffic carried by both LiFi and cellular networks.

Underwater localization system based on visible-light communications using neural networks.

Underwater localization using visible-light communications is proposed based on neural networks (NNs) estimation of received signal strength (RSS). Our proposed work compromises two steps: data collection and NN training. First, data are collected with the aid of Zemax OpticStudio Monte Carlo ray tracing software, where we configure 40,000 receivers in a $100\;{\rm m} \times 100\;{\rm m}$ area in order to measure the channel gain for each detector in seawater.

Optical wireless communication performance enhancement using Hamming coding and an efficient adaptive equalizer with a deep-learning-based quality assessment.

Optical wireless communication (OWC) technology is one of several alternative technologies for addressing the radio frequency limitations for applications in both indoor and outdoor architectures. Indoor optical wireless systems suffer from noise and intersymbol interference (ISI). These degradations are produced by the wireless channel multipath effect, which causes data rate limitation and hence overall system performance degradation.

Free-space 16-ary orbital angular momentum coded optical communication system based on chaotic interleaving and convolutional neural networks.

Recently, orbital angular momentum (OAM) rays passing through free space have attracted the attention of researchers in the field of free-space optical communication systems. Throughout free space, the OAM states are subject to atmospheric turbulence (AT) distortion leading to crosstalk and power discrepancies between states. In this paper, a novel chaotic interleaver is used with low-density parity-check coded OAM-shift keying through an AT channel.

Modulation format identification of optical signals: an approach based on singular value decomposition of Stokes space projections.

In this paper, two Stokes space (SS) analysis schemes for modulation format identification (MFI) are proposed. These schemes are based on singular value decomposition (SVD) and Radon transform (RT) for feature extraction. The singular values (SVs) are extracted from the SS projections for different modulation formats to discriminate between them.

On the performance of adaptive hybrid MQAM-MPPM scheme over Nakagami and log-normal dynamic visible light communication channels.

In this paper, we introduce the idea of using adaptive hybrid modulation techniques to overcome channel fading effects on visible light communication (VLC) systems. A hybrid $ M $M-ary quadrature-amplitude modulation ($ M{\rm QAM} $MQAM) and multipulse pulse-position modulation (MPPM) technique is considered due to its ability to make gradual changes in spectral efficiency to cope with channel effects. First, the Zemax optics studio simulator is used to simulate dynamic VLC channels.

Hybrid two-level MPPM-MDPSK modulation for high-speed optical communication networks.

A hybrid optical modulation approach is described, which layers a continuous wave $M$M-ary differential phase-shift keying ($M{\rm DPSK}$MDPSK) and a two-level ($2L$2L) multipulse pulse-position modulation (MPPM) intensity-modulated signal for improved spectral efficiency. These $2L$2L techniques are a generalization of earlier hybrid MPPM-$M{\rm DPSK}$MDPSK techniques and have the added advantage of reducing transmitter and detector complexities over previous hybrid modulation approaches. The spectral and power efficiencies for the proposed $2L$2L-MPPM-$M{\rm DPSK}$MDPSK modulation techniques are formulated and shown to have the highest spectral efficiency in comparison to other hybrid techniques with lower implementation complexity.

NLoS underwater VLC system performance: static and dynamic channel modeling.

In this paper, the impact of water channels under different communication link parameters is studied for underwater visible light communication (UVLC). The objective is to highlight the best results for non-line of sight (NLoS) communication links. In addition, NLoS links are studied under different parameters: LED colors, viewing angle, receiving angle, and data rates.

General silicon-on-insulator higher-order mode converter based on substrip dielectric waveguides.

A general silicon mode-converter waveguide that converts a fundamental mode to any higher-order mode is proposed. Specifically, dielectric substrip waveguides are inserted in the fundamental mode propagation path so that the conversion is done directly in the same propagation waveguide, without coupling the power into another waveguide as it happens in traditional mode converters. The device has a very small footprint compared to traditional converters.

Photonic crystal-based compact hybrid WDM/MDM (De)multiplexer for SOI platforms.

A compact hybrid wavelength- (WDM) and mode-division (de)multiplexer (MDM) is proposed, and its performance is evaluated. The design of the device is based on 2D photonic crystals with a square lattice and Si rods. The device can multiplex two eigenmodes, TM and TM, and two wavelengths, 1550 and 1300 nm.

Bidirectional mode-division multiplexers with antireflection gratings.

A bidirectional mode-division multiplexer (BMDM) with antireflection gratings is designed, and its performance in terms of S-parameters is presented. A BMDM can (de)multiplex three modes with only two waveguides and a Bragg grating. The impact of return losses on the performance of BMDMs is studied and antireflection gratings are designed to reduce their effects.

Modeling, simulation, and fabrication of bi-directional mode-division multiplexing for silicon-on-insulator platform.

A strip waveguide-based bi-directional mode-division multiplexer is proposed. A mathematical model has been proposed to analyze the performance, and the results are simulated. The design concept of this device to (de)multiplex three modes simultaneously has been studied previously for slab waveguides, both mathematically using the perturbative mode-coupled theory and by simulation using 2D FDTD Solutions (FDTD, finite difference time domain).

Performance evaluation of hybrid DPSK-MPPM techniques in long-haul optical transmission.

In this paper, we evaluate the performance of hybrid differential phase shift keying-multipulse pulse position modulation (DPSK-MPPM) techniques in long-haul nonlinear-dispersive optical fiber transmission. An expression for the nonlinear interference variance is obtained analytically using the Gaussian noise (GN) model. We derive upper-bound expressions that take into account the fiber nonlinearity impact on the DPSK-MPPM system's performance for both bit- and symbol-error rates (BER and SER).

Performance analysis of an all-optical OFDM system in presence of non-linear phase noise.

The potential for higher spectral efficiency has increased the interest in all-optical orthogonal frequency division multiplexing (OFDM) systems. However, the sensitivity of all-optical OFDM to fiber non-linearity, which causes nonlinear phase noise, is still a major concern. In this paper, an analytical model for estimating the phase noise due to self-phase modulation (SPM), cross-phase modulation (XPM), and four-wave mixing (FWM) in an all-optical OFDM system is presented.