ABSTRACT
As the global spread of COVID-19 becomes a rapidly evolving crisis, the development of contactless shared interactive displays is an urgent issue to reduce the risk of viral and bacterial cross contamination due to the use of touch-operated shared user terminals. Here, we experimentally demonstrate a contactless user terminal fabricated with a monolithic GaN Optoelectronic system (MGOS), which integrates the transmitter and receiver into a single chip. The inherent spectral emission-responsiveness overlap of GaN QW diodes gives the device a unique ability to detect light transmitted by diodes that share the same QW structure. When the GaN transmitter emits light to illuminate an external object, the integrated GaN receiver can detect the reflected light encoding the information and convert the optical signal into an electrical signal, so that the non-contact user terminal has the ability to use light for bidirectional data communication. Compared to traditional handwriting systems, these terminals operate as contactless information entry devices that can help reduce potential cross-contamination due to contact with handwriting terminals, provide precautions to keep the environment clean, and help prevent virus transmission. © 2023 IEEE.
ABSTRACT
Research and development at NTT Network Innovation Laboratories aims to establish elemental technologies for next-generation communication networks envisioned under NTT's Innovative Optical and Wireless Network (IOWN) and the 6th-generation mobile communication system (6G). These technologies, which include advanced and high-capacity backbone optical transmission networks and extended coverage of wireless communications, are being developed to support dramatic changes in the information society such as the expansion of remote work due to the COVID-19 pandemic. This article introduces optical/wireless transmission technologies and systemization technologies currently being researched and developed at NTT Network Innovation Laboratories. © 2022 Authors. All rights reserved.
ABSTRACT
We propose and demonstrate an optical chaos secured optical body area network (OBAN) employing polarization multiplexing and free space optics links. The physiological data of patient coded in non-return to zero on-off keying (NRZ-OOK) format from two on-body nodes modulated on orthogonal polarization states of a continuous wave (CW) laser is secured by using additive chaos masking (ACM) technique with chaotic waveforms generated through direct modulation of semiconductor chaotic lasers (CLs). After polarization multiplexing, the secure NRZ- OOK modulated optical signals are transmitted over indoor and outdoor free space optics (FSO) links based on GammaGamma channel model towards remote healthcare center. After chaos subtraction, the NRZ-OOK modulated optical signals are photodetected and passed on to bit error rate (BER) estimator for performance analysis. The electronic health (e-health) system based on the proposed OBAN provides adequate privacy for classified patient related information with added advantages of acceptable BER results, cost efficiency, speedy installation and suitable for use in current pandemic situation. © 2022 IEEE.
ABSTRACT
In January 2017, 'Psyche: Journey to a Metal World' was selected for implementation as part of NASA's Discovery program. The Psyche mission will utilize electric propulsion with SPT-140 Hall thrusters to rendezvous and orbit the metal-rich asteroid (16) Psyche, in the main asteroid belt between Mars and Jupiter. The Psyche spacecraft requires no chemical propulsion and, when launched in 2022, will be the first mission to use Hall thrusters beyond lunar orbit. The Psyche spacecraft is a hybrid development with Jet Propulsion Laboratory (JPL)-provided deep-space avionics and communications equipment mounted on a high-heritage MAXAR (formerly Space Systems Loral) Solar-Electric Propulsion (SEP) Chassis, based on their 1300 series of GEO communications satellites. The spacecraft is equipped to support a suite of science instruments, as well as a demonstration of the Deep Space Optical Communications (DSOC) technology. The spacecraft has sufficient onboard resources, autonomy, redundancy, and operability to complete a 3.5-year cruise to 16 Psyche, followed by a 20-month campaign of science investigations while orbiting the asteroid. The mission's early concept design and progress through Preliminary Design Review (PDR) has been described in previous work. The paper will cover the recent mission progress from the Critical Design Review (CDR) through the start of Spacecraft Environmental Testing, which took place during the COVID pandemic. The authors will highlight the successful remote collaboration between the major partners: ASU, JPL, MAXAR, and the Payload teams that led to the initiation of the Assembly, Test, Launch, Operations Phase (ATLO) in early March 2021. Emphasis will be placed on the effects that the COVID-19 pandemic had on the work environment over the last 16+ months, including challenges to delivery of flight hardware and test equipment. In addition to the COVID-19 challenges, other significant anomalies discovered during design and test will be described along with any impacts to the overall science capability of the mission. © 2022 IEEE.
ABSTRACT
The overall aim of this project is to investigate the application of a machine learning method in finding the optimized length of asleep time interval (TAS) in a cyclic sleep mechanism (CSM). Since past decade, the implementations of CSM in the optical network unit (ONU) to reduce the energy consumption in 10 gigabit-passive optical network (XG-PON) were extensively researched. However, the newest era sees the emergence of various network traffic with stringent demands that require further improvements on the TAS selection. Since conventional methods utilize complex algorithm, this paper presents the employment of an artificial neural network (ANN) to facilitate ONU to determine the optimized TAS values using learning from past experiences. Prior to simulation, theoretical analysis was done using the M/G/1 queueing system. The ANN was than trained and tested for the XG-PON network for optimal TAS decisions. Results have shown that towards higher network load, a decreasing TAS trend was observed from both methods. A wider TAS range was recorded from the ANN network as compared to the theoretical values. Therefore, these findings will benefit the network operators to have a flexibility measure in determining the optimal TAS values at current network conditions.
ABSTRACT
Networking technologies are fast evolving to support the request for ubiquitous Internet access that is becoming a fundamental need for the modern and inclusive society, with a dramatic speed-up caused by the COVID-19 emergency. Such evolution needs the development of networks into disaggregated and programmable systems according to the software-defined networking (SDN) paradigm. Wavelength-division multiplexed (WDM) optical transmission and networking is expanding as physical layer technology from core and metro networks to 5G x-hauling and inter- and intra-data-center connections requiring the application of the SDN paradigm at the optical layer based on the WDM optical data transport virtualization. We present the fundamental principles of the open-source project Gaussian Noise in Python (GNPy) for the optical transport virtualization in modeling the WDM optical transmission for open and disaggregated networking. GNPy approximates transparent lightpaths as additive white and Gaussian noise channels and can be used as a vendor-agnostic digital twin for open network planning and management. The quality-of-transmission degradation of each network element is independently modeled to allow disaggregated network management. We describe the GNPy models for fiber propagation, optical amplifiers, and reconfigurable add/drop multiplexers together with modeling of coherent transceivers from the back-to-back characterization. We address the use of GNPy as a vendor-agnostic design and planning tool and as physical layer virtualization in software-defined optical networking.
ABSTRACT
The fifth generation (5G) communication networks are supposed to be deployed worldwide since 2020. The coronavirus pandemic has partially limited the placement of this wireless communication towards sixth generation (6G) networks which are expected to provide global coverage and enhanced new transmission technologies. Motivated by the benefit of applying high-frequency millimeter-wave (mm-wave) carriers, which will greatly help in increasing the wireless network capacity, this paper proposes a communication system based on hybrid mm-wave transmission technologies over fiber/free space optical (FSO) backhaul link. Also, this work addresses the challenges when considering mm-waves for the current and futuristic mobile networks. Particularly, the proposed system offers a low latency communication link;also it can cope with the problems of the high path loss that face mm-wave wireless propagation by proposing an mm-wave over FSO instead. Furthermore, this system will increase the network coverage area by transmitting mm-waves to the areas with natural obstacles that are impossible laying fiber cables in it especially with emerging and disaster conditions. The performance of 64 GHz mm-wave over the proposed hybrid transmission link is investigated and the obtained results show that it succeeds in providing 10 Gbits/s with bit error rate (BER) about 1.5×10-13. Thus, it can be considered as a promising solution to overcoming difficulties in futuristic networks. © 2021 IEEE.
ABSTRACT
A single watchful sleep mode (WSM) combines the features of both cyclic sleep mode (CSM) and cyclic doze mode (CDM) in a single process by periodically turning ON and OFF the optical receiver (RX) of the optical network terminal (ONT) in a symmetric manner. This results in almost the same energy savings for the ONTs as achieved by the CSM process while significantly reducing the upstream delays. However, in this study we argue that the periodic ON and OFF periods of the ONT RX is not an energy efficient approach, as it reduces the ONT Asleep (AS) state time. Instead, this study proposes an adaptive watchful sleep mode (AWSM) in which the RX ON time of ONT is minimized during ONT Watch state by choosing it according to the length of the traffic queue of the type 1 (T1) traffic class. The performance of AWSM is compared with standard WSM and CSM schemes. The investigation reveals that by minimizing the RX ON time, the AWSM scheme achieves up to 71% average energy saving per ONT at low traffic loads. The comparative study results show that the ONT energy savings achieved by AWSM are 9% higher than the symmetric WSM with almost the same delay and delay variance performance.
ABSTRACT
AlGaN-based deep ultraviolet light-emitting diodes (UV LEDs) have gained rapidly growing attention due to their wide applications in water purification, air disinfection, and sensing as well as optical communication. Moreover, deep UV radiation has been verified as one of effective way to inactivate COVID-19. However, although numerous efforts have been made in deep UV LED chips, the reported highest external quantum efficiency (EQE) of them is 20.3%, which is far lower than that of visible LEDs. The EQE of commercial packaged AlGaN-based deep UV LEDs is usually lower than 5%, which will cause serious reliability problems as well. Therefore, it is very urgent to improve EQE and reliability of the devices from packaging level. In this review, a systematical summarization about the packaging technologies of AlGaN-based deep UV LEDs has been analyzed and future prospects have been made as well. Firstly, this work provides a brief overview of the devices and analyzes why the packaging level reduces EQE and reliability in theory. Then, systematically reviews the recent advances in packaging technologies and deep UV micro-LEDs. Finally, conclusions and outlooks are given as well. This review is of great significance for promoting the development of the packaging technologies for AlGaN-based deep UV LEDs. © 2022 Wiley-VCH GmbH
ABSTRACT
The iterative Fourier transform algorithm (IFTA) is widely used in various optical communication applications based on liquid crystal on silicon spatial light modulators. However, the traditional iterative method has many disadvantages, such as a poor effect, an inability to select an optimization direction, and the failure to consider zero padding or phase quantization. Moreover, after years of development, the emergence of various variant algorithms also makes it difficult for researchers to choose one. In this paper, a new intelligent hybrid algorithm that combines the IFTA and differential evolution algorithm is proposed in a novel way. The reliability of the proposed algorithm is verified by beam splitting, and the IFTA and symmetrical IFTA algorithms, for comparison, are introduced. The hybrid algorithm improves the defects above while considering the zero padding and phase quantization of a computer-generated hologram, which optimizes the directional optimization in the diffraction efficiency and the fidelity of the output beam and improves the results of these two algorithms. As a result, the engineers’ trouble in the selection of an algorithm has also been reduced.
ABSTRACT
Corona virus pandemic COVID19 has greatly affected the education sector. All academics institutes have to shut off face to face classroom teaching and learning. Engineering education, where there is a need to understand more of the practical concepts using costly hardware is greatly affected. One such engineering course, which involves this type of hardware, it requires practical understanding, is optical communication engineering. This paper describes how effectively this course will be taught from home using simulation tool. OPTSIM 5.0TM simulation tool is used to simulate all basic and advanced optical systems. Various optical systems and experiments such as Optical receiver, Optical Transmitter, Optical fiber amplifiers, Optical MUX, Optical De-MUX etc. can be designed for various fiber parameters and performance is measured using BER analyzer, Eye diagram analyzer, Optical Monitor, spectrum analyzer etc. This paper also describes how effectively the benefits of optical system and its performance using OPTSIM 5.0TM software will be taught in the virtual environment of teaching and learning.
ABSTRACT
The pandemic of COVID 19 virus has caused a lot of damage around the world. In addition to human lives, the economies of entire countries are at risk. In order to avoid business, health and education systems breakdown, it was necessary to find a new models of their functioning. An increasing number of these systems depends on IT support, so online teaching, obtaining information on health status and video conferencing meetings in business corporations has become a daily life. Although from the point of view of the end users of these systems, the result is information or data that has been processed, special attention should be highlighted to the transfer of information of various types through existing modern communication systems. In case that information of a great importance is intercepted or unreliable, the consequences can be catastrophic. Given the current situation at the global level and the importance of the information transmitted, in this paper we will focus on the protection and reliability of information transmission using adaptive transmission algorithms. Modeling and implementation of adaptive transmission algorithms can allow us to adapt the data rate with higher bandwidth or fixed data rate with lower bandwidth depending on the needs of end users and their requirements. Whether optical cables, radio frequency systems or modern wireless optical communication systems are used for the transmission of information, adaptive transmission algorithms can be successfully implemented and thus greater security and reliability of the transmitted information can be achieved. In addition to the model of adaptive transmission algorithms, the pseudocode of their functioning will be given in this paper. Finally, a comparative analysis of these algorithms observed through a measure of channel capacity will be graphically presented.