Although graphene's THz absorption rate increases with number of graphene layers, the absorbance is limited and unsatisfactory as a practicable absorber. Patterned graphene or graphene-based surface plasmon resonance has been proved to enhance THz absorption, but the performance is prone to be affected by graphene defects and local multilayer stacks. In this paper, we proposed to use a double circular metal ring (DCMR) array to enhance both the graphene's THz absorption with an ultrawide bandwidth and the tolerance of graphene's physical impurities. A DCMR array is patterned on the top surface of graphene layer with dielectric substrates, which excites a broadband spoof surface plasmons polaritons (SPPs) in the THz frequency range. The broadband spoof SPPs locally confine and strengthen THz wave interaction with graphene, and further enhance graphene's THz absorption, which is confirmed by numerically simulated dispersion relations. A four-layer graphene composite structure is fabricated to validate the scenario, which consists of graphene, a SiO2-capped doped-silicon substrate covered by graphene, and the DCMR array on the top surface of graphene. Time domain spectroscopy test shows that the THz absorption enhancement of the graphene composite with DCMR array covers the frequency range from 0.3 to 1.1 THz with 110% bandwidth. The THz absorption of the proposed graphene composite increases to more than 70% over a wide bandwidth of 77% at 0.65 THz compared with the graphene composite without DCMR array.

Lead zirconate titanate (PZT) exhibits a large Pockels coefficient and remnant polarization, making it a suitable candidate for integration in photonics circuits. In this work, a platform is developed to directly integrate PZT thin films on silicon-on-insulator (SOI) wafers to create electro-optic (EO) modulators.

This contribution discusses several recently proposed remote antenna units (RAUs) based on air-filled substrate-integrated-waveguide technology, specifically focusing on the co-design between antenna elements and optoelectronic transducers. These include two passive sub-6 GHz transmit RAUs and one active mmWave transmit RAU. It is concluded that the RAU's performance benefits from a thorough co-design, aiming for a conjugate-match between both components, when compared to a diakoptic design procedure, optimizing both components separately. Specifically, this approach resulted in a significant miniaturization of the sub-6 GHz RAU, while in case of the mmWave RAU, the efficiency was improved.

We introduce a new design space for optimizing III-V devices monolithically grown on Silicon substrates by extending the concept of nano-ridge engineering from binary semiconductors such as GaAs, InAs and GaSb to the ternary alloy InGaAs. This allows controlling the fundamental lattice constant of the fully relaxed ternary nano-ridge which thereby serves as a tunable base for the integration of diverse device hetero-layers. To demonstrate the flexibility of this approach, we realized an O-band nano-ridge laser containing three In0.45Ga0.55As quantum wells, which are pseudomorphically strained to an In0.25Ga0.75As nano-ridge base. The demonstration of an optically pumped nano-ridge laser operating around 1300 nm underlines the potential of this cost-efficient and highly scalable integration approach for silicon photonics.

A low-complexity and efficient mmWave-over-fiber remote antenna unit (RAU) is proposed for broadband transmission and wide-angle squint-free beam steering in the full [26.5–29.5] GHz n257 5G band. It leverages an optical beamforming network (OBFN), implemented on a silicon photonics integrated circuit, and a broadband optically enabled 1x4 uniform linear array (ULA). The antenna elements (AEs) of the ULA are implemented in air-filled substrate-integrated-waveguide technology. They adopt an improved aperture-coupled feeding scheme to achieve high efficiency, high isolation and minimal back radiation over a broad frequency band. Each AE is compactly integrated and co-optimized with a dedicated opto-electrical transmit chain, maximizing the RAU’s performance, including beamforming flexibility and energy efficiency, while minimizing its size. The separately packaged OBFN implements true-time-delay beamforming by means of four switchable optical delay lines that are capable of discretely tuning the delay difference between AEs with a resolution of 1.6 ps, up to a maximum delay of 49.6 ps to fully exploit the ULA’s full grating-lobe-free scan range. The measured AEs are excellently matched in the [25.1–30.75] GHz band, exhibit high isolation ($ >$15 dB) in the operating band, and feature a stable peak gain of 6.8 $\pm$ 0.72 dBi with a beamwidth of at least 95$^\circ$. Additionally, optical beamforming was successfully demonstrated by steering the RAU’s beam towards angles up to 51.8$^\circ$ without grating lobes. The optically enabled 1 × 4 ULA successfully establishes a 64-QAM wireless communication link at 2.2 Gbaud (13.2 Gbps) while beam steering up to 50$ ^\circ$ with an error vector magnitude below 7.6%.

Next-generation mobile networks will use mmWave frequencies as part of their strategy to meet the ever increasing wireless data rate demands. To mitigate the challenging propagation characteristics at these high frequencies, beamforming will be key. In this paper, we discuss a true time delay optical beamforming network (OBFN) based on switchable optical delay lines for $\mathrm{a}4 \times 1$ antenna array. This OBFN is implemented on a Si-Photonics platform and the delay lines are capable of discretely tuning the delay difference between elements with a resolution of 1.6 ps up to a maximum delay of 49.6 ps.

The emergence of new technologies and the era of IoT which will be based on compute-intensive applications. These applications will increase the traffic volume of today’s network infrastructure and will impact more on emerging Fifth Generation (5G) system. Research is going in many details, such as how to provide automation in managing and configuring data analysis tasks over cloud and edges, and to achieve minimum latency and bandwidth consumption with optimizing task allocation. The major challenge for researchers is to push the artificial intelligence to the edge to fully discover the potential of the fog computing paradigm. There are existing intelligence-based fog computing frameworks for IoT based applications, but research on Edge-Artificial Intelligence (Edge-AI) is still in its initial stage. Therefore, we chose to focus on data analytics and offloading in our proposed architecture. To address these problems, we have proposed a prototype of our architecture, which is a multi-layered architecture for data analysis between cloud and fog computing layers to perform latency- sensitive analysis with low latency. The main goal of this research is to use this multi-layer fog computing platform for enhancement of data analysis system based on IoT devices in real-time. Our research based on the policy of the OpenFog Consortium which will offer the good outcomes, but also surveillance and data analysis functionalities. We presented through case studies that our proposed prototype architecture outperformed the cloud-only environment in delay-time, network usage, and energy consumption.

The integration of III-V compound materials on Silicon is of paramount importance for the implementation of a complete Silicon Photonics platform where both active components, such as III-V laser diodes and amplifiers, and passive components are present. The monolithic growth of III-V materials on Si substrates is desirable in terms of cost efficiency, mass production and scalability. However, the large lattice mismatch between Si and most III-V compound materials of interest results in poor crystal quality for the deposited III-V film.

Edge-Fog Computing is closely related to IoT, 5G, and the blockchain, and various new technologies which are being actively studied in the fields of smart city, machine vision, and smart Industries. Specifically, the rapid growth and dissemination of high-performance sensing technologies with the ability to acquire high-level information, emphasis on the need and importance of further development of platforms like, edge-fog computing for the rapid processing and real-time response of various IoT based applications. In this paper, we introduce the work-in-progress an intelligent edge-to-edge and edge-to-fog collaborative computing platform, shortly called E-BItE, that enables collaborative processing in an edge-fog environment through elasticity and verify communicational functionality, performance and security through blockchain technology for smart city, smart machine-vision and smart Industries applications.

High-speed photodiodes often compromise responsivity in exchange for a reduced footprint. However, using waveguide photodiodes circumvents this limitation [1] . We combine uni-travelling-carrier photodiodes (UTC PDs) on a silicon nitride (SiN) photonic platform to achieve both high responsivity and high speed detectors. The SiN-platform has excellent properties such as low-loss waveguides and does not suffer from two-foton absorption at high optical power. A high responsivity is obtained through evanescent coupling of waveguide UTC photodiodes to SiN waveguides while still maintaining a small footprint.

Photonic integrated circuits (PICs) enable the miniaturization of optical quantum circuits because several optic and electronic functionalities can be added on the same chip. Integrated single photon emitters (SPEs) are central building blocks for such quantum photonic circuits. SPEs embedded in 2D transition metal dichalcogenides have some unique properties that make them particularly appealing for large-scale integration. Here we report on the integration of a WSe2 monolayer onto a Silicon Nitride (SiN) chip. We demonstrate the coupling of SPEs with the guided mode of a SiN waveguide and study how the on-chip single photon extraction can be maximized by interfacing the 2D-SPE with an integrated dielectric cavity. Our approach allows the use of optimized PIC platforms without the need for additional processing in the SPE host material. In combination with improved wafer-scale CVD growth of 2D materials, this approach provides a promising route towards scalable quantum photonic chips.

We present a novel approach for on-chip wavelength monitoring based on a digital Fourier Transform spectrometer. We demonstrate 130 nm operational bandwidth and an accuracy of 100 pm in the 2.3 μm wavelength range. © 2019 The Author(s)

Currently, one of the main objectives within the mid-IR community consists of reducing the dimensions and cost of sensing systems. Photonic integrated circuits (PICs) have been indicated as valuable candidates to achieve these goals thanks to their compactness, low cost (e.g. using CMOS-compatible platforms) and to their large versatility for applications such as multiplexing/demultiplexing or high detection throughput [1], [2].

We demonstrate a broadband digital Fourier Transform (dFT) spectrometer addressing wavelength monitoring applications in the 2.3-μm wavelength range. The spectrometer is built in a silicon-on-insulator platform and the design allows its fabrication with CMOS-compatible tools. We report an operating bandwidth of 130 nm around 2.3-μm wavelength using an efficient algorithm for sparse spectra to retrieve the wavelength with an accuracy of 100 pm. The spectrometer can also resolve two laser lines up for dFT spectrometers, which takes advantage of the sparse nature of the spectrum.

Introduction : Tobacco use is a major factor for non-communicable diseases like cerebrovascular accidents, acute coronary syndrome, hypertension, debilitating chronic diseases like atherosclerosis and chronic obstructive pulmonary disease. Tobacco use is a bad habit that starts before the accomplishment of adulthood, and young people, specifically, are more in prone to create nicotine addiction. Nursing faculty can also teach and advice all students to change their state of mind in regards to tobacco utilization and help them to quit the use tobacco. Methods: Quasi experimental study performed on 54 male high school students to evaluate the effectiveness of health teaching session about the knowledge of tobacco use ill-effects. Results: Findings revealed that the mean post-test mean score was significantly higher than their mean pre-test score. The calculated “t” value (t=-88.520 p<0.005) was greater than the table value at 0.05 in all sections. Therefore, the null hypothesis Conclusions: It is concluded that the educational program is effective in enhancing the knowledge of students regarding ill- effects of tobacco use. Keywords -, Health Teaching Program, Knowledge, and Tobacco use ill-effects. DOI : 10.7176/JHMN/67-10 Publication date :October 31 st 2019

Rare-earth ion doped potassium yttrium double tungstate, RE: KY(WO4)(2), is a promising candidate for small, power-efficient, on-chip lasers and amplifiers. There are two major bottlenecks that complicate the realization of such devices. Firstly, the anisotropic thermal expansion coefficient of KY(WO4)(2) makes it challenging to integrate the crystal on glass substrates. Secondly, the crystal layer has to be, for example, < 1 mu m to obtain single mode, high refractive index contrast waveguides operating at 1550 nm. In this work, different adhesives and bonding techniques in combination with several types of glass substrates are investigated. An optimal bonding process will enable further processing towards the manufacturing of integrated active optical KY(WO4)(2) devices. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

We demonstrate the coupling of localized excitons from a WSe2 monolayer into a silicon nitride waveguide by measuring the waveguide-coupled fluorescence, paving the way towards scalable fabrication of on-chip single photon sources.

We present a Vernier tunable racetrack resonator filter on Ge-on-SOI, with 110 nm FSR at 5 μm. The racetrack has a Q-factor of 20000 and side-peak suppression >20 dB, sufficient for wavelength selection in an external cavity laser.

Surface enhanced Raman spectroscopy (SERS) is a widely known sensing technique that uses a plasmonic enhancement to probe analytes in ultra-small volumes. Recently, the integration of plasmonic structures with photonic integrated waveguides promised the full integration of a SERS system on a chip. Unfortunately, the previously reported sensors provide modest overall SERS enhancement resulting in a limited signal to noise ratio. Here, we report a photonic waveguide interfaced SERS sensor that shows an order of magnitude higher pump to Stokes conversion efficiency and lower background than previous realizations. Moreover, the plasmonic structure is fabricated without the use of e-beam lithography but rather using a combination of atomic layer deposition and deep UV photolithography. We investigate numerically the performance of the sensor in terms of Raman conversion efficiency for various design parameters. The experimental results are presented via the acquisition of SERS spectra that show a conversion efficiency of 10−9 for a monolayer of 4-nitrothiophenol. To explore the broadband characteristic of our sensor in the therapeutic spectral window, two different pump wavelengths, i.e., 632 and 785 nm, are used. To the best of our knowledge, this is the first ever broadband SERS demonstration of an on-chip Raman sensor. We further study the reproducibility of our SERS sensor, reaching a relative standard deviation of the acquired spectra (RSD) < 5%.