Optical Networks: An Overview

2021 ◽  
pp. 3-22
Author(s):  
Debasish Datta

We present an overview of optical networks, beginning with a background of today’s telecommunication networks and the roles of optical fibers therein. Next, we describe the chronology of developments in telecommunication networks starting from the days of public-switched telephone network (PSTN) offering ‘plain old telephone service’ as the basic service, followed by the divestiture of Bell Laboratories and subsequent developments of the demonopolized regime of telecommunication networks with multiple services offered to users by the same network providers. Then we describe the salient features of the two generations of optical networks for various network segments, including single-wavelength and WDM-based LANs/MANs, accesses networks, metro and long-haul networks, datacenters, and elastic optical networks. Finally, we discuss briefly the possible network architectures with the evolving optical-networking technologies. (124 words)

2002 ◽  
Vol 4 (1) ◽  
pp. 246-261 ◽  
Author(s):  
James J. Refi

2020 ◽  
Author(s):  
Chathuranga M. Wijerathna Basnayaka ◽  
Dushantha Nalin K. Jayakody

With the advancement in drone technology, in just a few years, drones will be assisting humans in every domain. But there are many challenges to be tackled, communication being the chief one. This paper aims at providing insights into the latest UAV (Unmanned Aerial Vehicle) communication technologies through investigation of suitable task modules, antennas, resource handling platforms, and network architectures. Additionally, we explore techniques such as machine learning and path planning to enhance existing drone communication methods. Encryption and optimization techniques for ensuring long−lasting and secure communications, as well as for power management, are discussed. Moreover, applications of UAV networks for different contextual uses ranging from navigation to surveillance, URLLC (Ultra-reliable and low−latency communications), edge computing and work related to artificial intelligence are examined. In particular, the intricate interplay between UAV, advanced cellular communication, and internet of things constitutes one of the focal points of this paper. The survey encompasses lessons learned, insights, challenges, open issues, and future directions in UAV communications. Our literature review reveals the need for more research work on drone−to−drone and drone−to−device communications.


2014 ◽  
Vol 25 (1) ◽  
pp. 169-185
Author(s):  
Samuel Ángel Jaramillo Flórez ◽  
Yuli Fernanda Achipiz

The bioelectronics takes of the biology the optimized elements for to do a copy and to build technological mechanisms with functions based in that of body lives components. Telecommunications and biology present an analogy between the optical receivers and insects eyes, which forms are adequate to receipt signal since a transmitter, and these are been leaded to perfection by the nature during millions of years in the environment adaptation. The sizes and the forms depend of the direction of the waves and of the radiation pattern of these biotransmitters and bioreceivers (omatidies of insects eyes), which is similar as the optical communications emitters and photodetectors. The growth of the telecommunication services makes necessary the optimization of the bandwidth of the transmission channels. Although the optic transmission is considered like the ideal as for the attenuation and distortion characteristics that make that it possesses the better relation bandwidth - longitude, the demand of more transmission capacity forces to take advantage of them efficiently. High costs generated when deploying Optic Fiber Networks at the transport level, together with other factors that avoid PONs arriving to the home and/or office, have impulsed the design and implementation of partially optical networks (FITL), including an alternative that uses infrared light. This work explores the basis of these news access networks, and it is presented an optical communication transmission/reception system with optic channel of free space where has been modulated the transmitter laser through a set of spherical lens and optical fibers that expand the beam of light to different points of an indoor enclosure producing multiple punctual images located in positions that permit to determine and to optimize the bandwidth of the system. The computational simulation results are showed and are compared with those experimentally measured, indicating that this is an original method for to design emitters and receivers of high performance for optical communications.


Author(s):  
Muhammad Ishaq ◽  
Mohammad Kaleem ◽  
Numan Kifayat

This chapter briefly introduces the data center network and reviews the challenges for future intra-data-center networks in terms of scalability, cost effectiveness, power efficiency, upgrade cost, and bandwidth utilization. Current data center network architecture is discussed in detail and the drawbacks are pointed out in terms of the above-mentioned parameters. A detailed background is provided that how the technology moved from opaque to transparent optical networks. Additionally, it includes different data center network architectures proposed so far by different researchers/team/companies in order to address the current problems and meet the demands of future intra-data-center networks.


Author(s):  
Said Zaghloul ◽  
Admela Jukan

The architecture, and protocols for authentication, authorization, and accounting (AAA) are one of the most important design considerations in third generation (3G)/fourth generation (4G) telecommunication networks. Many advances have been made to exploit the benefits of the current systems based on the protocol remote authentication dial in user service (RADIUS)protocol, and the evolution to migrate into the more secure, robust, and scalable protocol Diameter. Diameter is the protocol of choice for the IP multimedia subsystem (IMS) architecture, the core technology for the next generation networks. It is envisioned that Diameter will be widely used in various wired and wireless systems to facilitate robust and seamless AAA. In this chapter, we provide an overview of the major AAA protocols RADIUS and Diameter, and we discuss their roles in practical 1xEV-DO network architectures in the three major network tiers: access, distribution, and core. We conclude the chapter with a short summary of the current and future trends related to the Diameter-based AAA systems.


2021 ◽  
pp. 23-132
Author(s):  
Debasish Datta

The technologies used in optical networks have evolved seamlessly over the past six decades. Optical fibers with extremely low loss and enormous bandwidth are used as the transmission medium, while semiconductor lasers and LEDs serve as optical sources, and the photodetectors – pin and avalanche photodiodes – are used to receive the optical signal at the destination nodes. The transmitted optical signal has to pass through a variety of network elements, which in turn need a wide range of passive and active devices, carrying out the necessary networking functionalities. For WDM optical networks, many of these tasks need to be accomplished in the optical domain itself in a wavelength-selective manner, calling for various types of WDM-based networking elements. In this chapter, we present a comprehensive description of the optical and optoelectronic devices that are used in today’s optical networks. (137 words)


2021 ◽  
pp. 299-320
Author(s):  
Debasish Datta

In TDM PONs, or simply PONs, the transmission capacity of optical fibers remains under-utilized with single-wavelength transmissions for both upstream and downstream traffic. Use of WDM transmission in PONs can significantly enhance the overall network capacity and coverage area. WDM transmission in PONs can be realized in several ways, such as by using WDM exclusively or combining WDM with TDM, leading to WDM PONs and TDM-WDM PONs (TWDM PONs). This chapter gives several candidate physical configurations to realize WDM and TWDM PONs, and describes some useful dynamic wavelength-bandwidth allocation (DWBA) schemes for the latter. We also briefly discuss the needs of open access to the PON-based access networks for the various stakeholders, such as service providers and network providers. Finally, we describe briefly the roles of optical networking in the access segment of mobile networks. (135 words)


Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6370
Author(s):  
Krzysztof Przystupa ◽  
Mykola Beshley ◽  
Mykola Kaidan ◽  
Volodymyr Andrushchak ◽  
Ivan Demydov ◽  
...  

In communication networks, the volume of traffic, the number of connected devices and users continues to grow. As a result, the energy consumption generated by the communication infrastructure has become an important parameter that needs to be carefully considered and optimized both when designing the network and when operating it in real-time. In this paper, the methodology of calculation of complex parameters of energy consumption for transport telecommunication networks is proposed. Unlike the known techniques, the proposed methodology takes into account heterogeneity and multilayer networks. It also takes into account the energy consumption parameter during the downtime of the network equipment in the process of processing the service data blocks, which is quite an important task for improving the accuracy of energy consumption at the stage of implementing the energy-saving network. We also developed simulation software to estimate and manage the energy consumption of the optical transport network using the LabVIEW environment. This software tool allows telecommunication network designers to evaluate energy consumption, which allows them to choose the optimal solution for the desired projects. The use of electro-and acousto-optical devices for optical transport networks is analyzed. We recommended using electro-optical devices for optical modulators and acousto-optical devices for optical switches. The gain from using this combination of optical devices and the parameter of rij electro-optical coefficient and M2 acousto-optical quality parameter found in the paper is about 36.1% relative to the complex criterion of energy consumption.


Photonics ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 37 ◽  
Author(s):  
Anton V. Bourdine ◽  
Vladimir A. Burdin ◽  
Vijay Janyani ◽  
Ashish Kumar Ghunawat ◽  
Ghanshyam Singh ◽  
...  

This work presents an alternative fast and simple method for the design of a refractive index profile of silica multimode optical fibers (MMFs) with extremely enlarged core diameters of up to 100 µm for laser-based multi-gigabit short-range optical networks. We demonstrate some results of 100 µm core MMF graded index profile optimization performed by a proposed solution, which provides a selected mode staff differential mode delay (DMD) reduction over the “O”-band under particular launching conditions. Earlier on, a developed alternative model for a piecewise regular multimode fiber optic link operating in a few-mode regime for the computation of laser-excited optical pulse dynamics during its propagation over an irregular silica graded-index MMF with an extremely large core diameter, is utilized to estimate the potentiality of fiber optic links with the described MMFs. Here, we also present the comparison results of the simulation of 10GBase-LX optical signal transmission over 100 µm core MMFs with conventional and optimized graded-index refractive index profiles.


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