scholarly journals Survey on underwater optical wireless communication: perspectives and challenges

2019 ◽  
Vol 13 (1) ◽  
pp. 138 ◽  
Author(s):  
Tejaswini R Murgod ◽  
S Meenakshi Sundaram
Keyword(s):  
Optical Communication ◽  
Network Architecture ◽  
High Speed ◽  
Data Transfer ◽  
Propagation Delay ◽  
Underwater Communication ◽  
Communication Performance ◽  
High Attenuation ◽  
Transmission Distance ◽  
Data Rates

<div><p class="Affiliation">The demand for underwater communication is growing at a faster pace since few decades. Maximizing the communication performance and building efficient network architecture for underwater communication is a challenging task. Due to the reduced bandwidth, high error rate, noise, propagation delay, water currents and increased cost in the network topology, the existing communication techniques are not feasible for underwater communication. Research in high speed underwater transmission technology has become a primary need in today’s world. By using underwater acoustic sensor network high transmission distance can be achieved but with lower data rates, high power consumption, larger delays and with higher cost. Underwater Optical Communication can be used to increase data rates and lower delays but it suffers from high attenuation due to which it cannot be used for data transfer over larger distances. Research in the area of hybrid sensor networks is a challenging task and has many open research challenges, which needs to be solved. In this paper we discuss the various architectures of underwater communication. A comparative study is made on different routing protocols and localization algorithms. The challenges faced by acoustic and optical communication are also discussed.</p></div>

scholarly journals Laser technologies of data transfer in aquatic environment in the organization of underwater wireless communication networks

2021 ◽  
pp. 80-85
Author(s):  
В.Л. Мартынов ◽  
В.И. Дорошенко ◽  
Н.М. Божук ◽  
Ю.Г. Ксенофонтов
Keyword(s):  
Communication Networks ◽  
Optical Communication ◽  
Aquatic Environment ◽  
Communication Systems ◽  
High Speed ◽  
Data Transfer ◽  
Open Systems ◽  
Transmission Rate ◽  
Video Data ◽  
Optical Communication Systems

Решению вопросов, связанных с телекоммуникационным оборудованием, функционирующем в водной среде, в настоящее время уделяется особое внимание. На смену традиционным подводным системам обмена информацией в гидроакустических полях приходят открытые системы её оптической передачи и приёма, базирующиеся на лазерных технологиях. Это вызвано необходимостью трансляции с высокой разрешающей способностью видеоданных, среди которых, например, может быть либо визуальное отображение подводных систем в динамике, либо результаты мониторинга объектов подводной инфраструктуры в реальном масштабе времени, либо что-то другое с учётом требований Заказчика. Канал передачи такого большого объёма информации при условии ее считывания с задаваемым качеством должен иметь пропускную способность более 1 Мбит/с. Такую высокую скорость передачи невозможно реализовать в подводных гидроакустических системах, граница технических возможностей которых на превышает 10...50 кбит/с. В аналогичной ситуации при заданных параметрах канала связи частоты несущих оптического диапазона имеют порядок 1014 Гц, что обеспечивает динамический диапазон полосы пропускания в районе 1012…1013 Гц. С учётом условия квазимонохроматичности применение гидроакустических средств для передачи видеоданных становится проблематичным, так как техническая реализация такой задачи потребует слишком большого времени. С учётом сказанного, преимуществом подводных беспроводных оптических систем связи является их высокая широкополосность, которая обеспечит высокую скорость передачи данных. В статье обосновывается целесообразность использования открытых оптических системы связи для создания высокоскоростных подводных инфотелекоммуникаций, среди которых наиболее предпочтительными являются лазерные системы. Special attention is currently paid to the solution of issues related to telecommunication equipment operating in the aquatic environment. The traditional underwater systems for the exchange of information in hydroacoustic fields are being replaced by open systems for its optical transmission and reception, based on laser technologies.This is due to the need to broadcast high-resolution video data, among which, for example, there can be either a visual display of underwater systems in dynamics, or the results of monitoring objects of underwater infrastructure in real time, or something else, taking into account the requirements of the Customer. The transmission channel of such a large amount of information, provided it is read with a specified quality, must have a bandwidth of more than 1 Mbit / s. Such a high transmission rate cannot be realized in underwater sonar systems, the technical capabilities limit of which does not exceed 10 ... 50 kbit/s. In a similar situation, given the parameters of the communication channel, the carrier frequencies of the optical range are 1014 Hz, which provides a dynamic bandwidth range about 1012…1013Hz. Taking into account the condition of quasimonochromaticity, the use of hydroacoustic means for transmitting video data becomes problematic, since the technical implementation of such a task will take too long. In view of the above, the advantage of underwater wireless optical communication systems is their high broadband, which will provide a high data transfer rate. The article substantiates the expediency of using open optical communication systems for creating high-speed underwater information telecommunications, among which the most preferable are laser systems.

scholarly journals High-Speed Light Signal Transmitters for Optical Communication Based on Ultraviolet Radiation

2020 ◽  
Vol 10 (2) ◽  
pp. 693
Author(s):  
Xin Li ◽  
Yue Wu ◽  
Jialei Yuan ◽  
Shuyu Ni ◽  
Chuan Qin ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Optical Communication ◽  
High Speed ◽  
Light Output ◽  
Light Signal ◽  
Communication Performance ◽  
Ultraviolet Range ◽  
Space Data ◽  
Dominant Peak ◽  
Transmission Test

A light signal transmitter based on ultraviolet radiation is realized on GaN-on-silicon platform. The light signal transmitter with ultra-small active area is fabricated by a double-etching process. The absolute value of negative junction capacitance of transmitter is as low as the pF (picofarads) scale in positive bias voltage. Small capacitance is beneficial to improve the communication performance of a transmitter. The dominant EL (electroluminescence) peak of transmitter is located at about 380 nm in the ultraviolet range. With the increase of the current, the dominant peak of transmitter remains stable and the light output power is lineally modulated. A free-space data transmission test in the ultraviolet range with 250 Mbps was conducted to indicate a promising high-speed optical communication capability of a light signal transmitter in the ultraviolet range.

scholarly journals Quantum security and 6G critical infrastructure

2021 ◽  
Vol 6 (1) ◽  
pp. 1-8
Author(s):  
Miloslav Hoschek
Keyword(s):  
Network Architecture ◽  
High Speed ◽  
Critical Infrastructure ◽  
Internet Communication ◽  
New Paradigm ◽  
Quantum Communications ◽  
Time Zone ◽  
Network Nodes ◽  
Data Rates ◽  
Wireless Standards

In the mid 2030-s in the field of defense and national security communications the quantum computers and 6G artificial intelligence will have domination. 6G communication is accepted in a variety of mobile data comparts transmitted through spectral technologies. The human body becomes a part of the 6G network architecture. A set of network nodes or wearable devices, embedded sensors or nanodes collect confidential information that is exchanged for multiple purposes, such as health, statistics, and safety. An important part of the 6G new paradigm will be intelligent reflective surfaces, quantum teleportation, quantum encrypted messaging, 6G holography, distributed ledger, 6G layer security threats. The 6G wireless standards will allow real-time time zone high-speed internet communication with 1TB data per second. The radio frequency networks, THZ communications, molecular communications, and quantum communications will dramatically improve data rates.

Evaluation of Proposed Coherent Optical OFDM Link Using X-QAM with Polarization Division Multiplexing

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Suresh Kumar ◽  
Akshaya Dhingra ◽  
Payal Arora
Keyword(s):  
Communication Networks ◽  
Optical Communication ◽  
Orthogonal Frequency Division Multiplexing ◽  
Data Transfer ◽  
Large Data ◽  
Communication Model ◽  
Frequency Division ◽  
Data Rates ◽  
Optical Ofdm ◽  
Polarization Division Multiplexing

AbstractOrthogonal Frequency Division Multiplexing (OFDM) is one of the popular techniques used for 4 G, 5 G and backbone optical communication networks to meet the large data transfer requirement applications. Optical Communication model based on Coherent Optical OFDM (CO-OFDM) using 4-Quadrature Amplitude Modulation (QAM), 16-QAM and 64-QAM has been evaluated by different researchers. To understand and evaluate the effects of polarization, we have proposed an Optical Communication model with Polarization Division Multiplexing (PDM). The proposed CO-OFDM PDM system has been evaluated for different link lengths of 50, 100 and 150 km at varying data rates of 10, 20 and 30 Gbps. The performance of the designed link has been evaluated in terms of Q-factor, Bit Error Rate (BER), Optical Spectrum and constellation diagram. The results clearly exhibit that the Q-factor, BER and constellations are superior when PDM is incorporated with the CO-OFDM link using X-QAM.

Solitons based optical packet switch analysis

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Utkarsh Shukla ◽  
Niraj Singhal ◽  
Rajiv Srivastava
Keyword(s):  
Wavelength Division Multiplexing ◽  
Optical Communication ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Data Transfer ◽  
Wavelength Converters ◽  
Wavelength Division ◽  
Soliton Pulse ◽  
Packet Switch ◽  
High Speed Data

Abstract Due to the evolution of data centric applications demand for high speed data transfer and more bandwidth is increasing continuously. The unavailability of components like tunable wavelength converters (TWCs) restrict the transfer of parallel information using wavelength division multiplexing (WDM), therefore in the present scenario optical orthogonal frequency division multiplexing can be used. Moreover in optical communication narrow Gaussian pulses are transmitted, which spread with distance and leads to the broadening of the pulse and pulse peak power goes down and thus limits the system. In this paper a Soliton based optical communication system is proposed and its comparison with Gaussian pulse is presented and it has been found that soliton pulse has lesser bit error rate in comparison to Gaussian pulses.

scholarly journals Multiplexed Quantum Random Number Generation

Quantum ◽  
2019 ◽  
Vol 3 ◽  
pp. 141 ◽  
Author(s):  
Ben Haylock ◽  
Daniel Peace ◽  
Francesco Lenzini ◽  
Christian Weedbrook ◽  
Mirko Lobino
Keyword(s):  
High Speed ◽  
Random Number ◽  
Data Transfer ◽  
Random Number Generator ◽  
Random Number Generation ◽  
Generation Rate ◽  
Number Generation ◽  
Data Rates ◽  
Integrated Optical ◽  
Encrypted Communication

Fast secure random number generation is essential for high-speed encrypted communication, and is the backbone of information security. Generation of truly random numbers depends on the intrinsic randomness of the process used and is usually limited by electronic bandwidth and signal processing data rates. Here we use a multiplexing scheme to create a fast quantum random number generator structurally tailored to encryption for distributed computing, and high bit-rate data transfer. We use vacuum fluctuations measured by seven homodyne detectors as quantum randomness sources, multiplexed using a single integrated optical device. We obtain a real-time random number generation rate of 3.08 Gbit/s, from only 27.5 MHz of sampled detector bandwidth. Furthermore, we take advantage of the multiplexed nature of our system to demonstrate an unseeded strong extractor with a generation rate of 26 Mbit/s.

scholarly journals Passive Equalization Networks—Efficient Synthesis Approach for High-Speed Signal Integrity Characterization

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1222
Author(s):  
Diana Brinaru
Keyword(s):  
High Speed ◽  
Constant Input ◽  
Microstrip Technology ◽  
Eye Diagram ◽  
High Attenuation ◽  
High Data ◽  
Filter Synthesis ◽  
Data Rates ◽  
New Variant ◽  
The Cost

High data rates challenges and long traces from current state-of-the-art systems imply high attenuation. In the present article, we will present a detailed process of synthesis of equalizers, for choosing the correct one for a given application. The methods are based on scattering parameters applied on interconnections modeled as microstrip or stripline. Firstly, one may have an overview of types of equalizers, passive, active, and adaptive ones, and a detailed filter synthesis is applied in microwave systems having as start point the insertion loss of a given trace on a given substrate. Next, time domain analyses offer a better understanding of the performance of the interconnect, based on eye diagram inspection and the variation of waveforms with time. Finally, we will present results based on simulation of the equalizers network in a microstrip technology followed by discussions and conclusions. The study proposes to use equalizers in either the transmitter or receiver point, proposes a bridge equalizer with the cost of additional elements but improved constant input, output impedance, and also a new variant for single ended trace based on microwave resonator is proposed. Performance is demonstrated by results from simulations.

Modeling and spectral analysis of high speed optical fiber communication with orthogonal frequency division multiplexing

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Demissie Jobir Galmecha ◽  
Bekele Tesema Hora ◽  
Ram Sewak Singh
Keyword(s):  
Optical Fiber ◽  
Optical Communication ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Direct Detection ◽  
Coherent Detection ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Transmission Systems ◽  
Data Rates

Abstract Optical communication has emerged as the best solution to high-speed transmission systems due to its higher bandwidth and higher data rates. The higher data rates with simple transmitter and receiver modeling are one of the best solutions to design the spectrally efficient high-speed optical transmission system using different modulation techniques. In the recent past, optical communication networks have been specifically designed and optimized to support different communication standards increasing the capabilities of optic fiber, integrated waveguides, and related optical fiber hardware, and signal conditioning circuits. So, this research paper presents a study, modeling, simulation, and analysis of optical performance under different transmission systems which are considered in a practical high-speed design using orthogonal frequency division multiplexing (OFDM). This can be done by using both coherent detection OFDM and direct detection OFDM to minimize dispersion effects in optical communication because OFDM is basic for modern technology to increase the data rate and increase the requirement of bandwidth in broadband services. Many optical fiber problems, such as chromatic dispersion (CD) and polarization mode dispersion (PMD) are solved using OFDM. The performance analyses made in this work by using different parameters such as bit error rate (BER), optical signal-to-noise ratio (OSNR), quality (Q) factor at different distance transmission by using different quadrature modulation such as 4-QAM, 16-QAM, 32-QAM, and 64-QAM to maintain the OSNR value, spectral efficiency, and the required data rates. The simulated results have shown that the coherent detection OFDM and direct detection OFDM with considered QAM provides the best value of BER and quality of the signal at a specific distance.

scholarly journals Reliability Scaling of Nanoscale Avalanche Photodiodes in High-Speed Optical Communication

2019 ◽  
Vol 11 (6) ◽  
pp. 1
Author(s):  
Jack Jia-Sheng Huang ◽  
H. S. Chang ◽  
Yu-Heng Jan
Keyword(s):  
Optical Communication ◽  
High Speed ◽  
Avalanche Photodiodes ◽  
Building Blocks ◽  
Breakdown Field ◽  
Degradation Model ◽  
Device Scaling ◽  
High Data ◽  
Data Rates ◽  
Device Miniaturization

In the present era of big data and 5G wireless, both microelectronic and photonic components are indispensable building blocks. For microelectronics, device miniaturization has been following Moore&rsquo;s law to attain higher speed and greater functionality. For photonics, similar device scaling is also evolving in both lasers and photodiodes to transmit high data rates of 25 Gb/s and beyond. However, such device miniaturization may impose challenges such as reliability and fabrication that require careful scientific and engineering studies. In particular, the reliability understanding of photonic device scaling is fairly rudimentary with only scattered reports. In this paper, we study the device and reliability scaling of nanoscale avalanche photodiodes (APDs). The device miniaturization of APDs mainly involves thickness reduction in the charge control and multiplication layers. The layer reduction however causes an increase in breakdown field that may adversely affect reliability in several aspects such as electrical/optical overload and electrostatic discharge (ESD). We present a new reliability degradation model of APDs based on the breakdown field and correlate it with the experimental data. Empirical reliability equations are instituted to establish quantitative formulation. We discuss the overload and ESD performances as a function of breakdown field for both planar-type and mesa-type APD structures.

scholarly journals High Speed OTDM-DWDM Bit Compressed Network for Long-Haul Communication

2019 ◽  
Vol 18 (2) ◽  
pp. 57-65
Author(s):  
Tadbirul Islam ◽  
Mohammad Nasir Uddin
Keyword(s):  
High Speed ◽  
Data Transfer ◽  
Time Window ◽  
Single Mode ◽  
Optical Amplifier ◽  
Optical Signal ◽  
Single Mode Fiber ◽  
Sequence Length ◽  
Transmission Distance ◽  
Communication Network Design

This paper represents an optical communication network design that incorporates both OTDM and DWDM techniques which provides up to 240 Gbit/s data transfer rate, long-haul communication distance of 2700 km with a maximum number of 384 channels in this designed architecture. Each channel has a bitrate of 625 Mbit/s that follows optical signal hierarchy OC-12, STS-12 (SONET ANSI), and STM-4 (SDH CCITT), and the design maintains standard parameters for commercially available channel grids at 100 GHz spacing. The communication is done by Single Mode Fiber (SMF) of 50 km and Dispersion Compensating Fiber (DCF) of 10 km followed by one optical amplifier gain in each span. Bit error rate (BER) remains significantly low while transmission distance for only OTDM is 18000 km at a BER < 10-12, and for the hybrid OTDM-DWDM it is 2700 km at a BER < 10-16. Both values are measured under 128 bits sequence length. Three compression stages are used for 8 channels each in order to minimize the gap between bits, and to utilize the space for more channels within a specific time window.

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