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This article discusses novel wireless and optical technologies to address the radical new challenges of small cell mobile backhaul (MBH). Specifically, we examine 60 GHz and 70-80 GHz millimeter-wave technologies for high-capacity last mile and pre-aggregation backhaul, and orthogonal frequency-division multiple access passive optical networks as the optical technology complement for enabling flexible cost-efficient hybrid backhaul coverage. Flexible high-capacity hybrid millimeter wave/optical MBH network operation is next verified via network simulations in the context of a demanding, urban small-cell backhaul application. Finally, a novel software defined networking tool called the backhaul resource manager is introduced for automated dynamic resource provisioning and capacity-aware path computation that improves fairness, network utilization and end-to-end user quality of experience. The introduction of the novel wireless, optical, and software-defined technologies thus has the potential to truly revolutionize the future MBH network.

Future high-performance computing systems will require optical I/O to achieve their aggressive bandwidth requirements of multiple terabytes per second with energy efficiency better than 1 pJ/b. Near-term optical I/O solutions will integrate optical and electrical components in the package, but longer-term solutions will integrate photonic elements directly into the CMOS chip to further improve bandwidth and energy efficiency. The presented near-term optical I/O uses a customized package to assemble CMOS integrated transceiver circuits, discrete VCSEL/detector arrays, and polymer waveguides. Circuit simulations predict this architecture will achieve energy efficiency better than 1 pJ/b at the 16 nm CMOS technology node. Monolithic photonic CMOS process technology enables higher bandwidth and improved energy efficiency for chip-to-chip optical I/O through integration of electro-optical polymer based modulators, silicon nitride waveguides, and polycrystalline germanium (Ge) detectors into a CMOS logic process. Experimental results for the photonic CMOS ring resonator (RR) modulators and Ge detectors demonstrate performance at up to 40 Gb/s and analysis predicts that photonic CMOS will eventually enable energy efficiency of 0.3 pJ/b with 16 nm CMOS. Optical interconnect technologies with multilane communication or wavelength-division multiplexing will further increase bandwidth to provide the multiple-terabyte-per-second optical interconnect solution that enables scaling of high-performance computing into and beyond the tera-scale era.

The OptoElectronics and Communications Conference (OECC) has been a signature event in the area of optoelectronic and optical communications. This year, OECC 2009, the 14th in the series, was held in Hong Kong SAR, China, from 13 to 17 July 2009. With its superb facilities, professional service, and sophistication, the Hong Kong Convention and Exhibition Centre was selected to be the conference venue. It is also internationally known as the best exhibition and convention center in Asia for its excellence in hosting some of the world's greatest events.

The dramatic increase in capacity of telecommunication networks since the mid-1970s has been enabled by the introduction of light-wave systems for transmission. Since that time, services have evolved from voice and fax at 64 kbit/s to Ethernet and other data services at many Gbit/s, while the transmission technologies have evolved from GaAs 850 nm semiconductor lasers over multimode fiber to single mode fiber systems operating at 1300 nm, and later to multiwavelength systems operating at 1550 nm. This paper describes the evolution in services, frame formats, and optical technology along with the supporting ITU-T standardization activities that have fueled this development.

The explosion of current demand has brought the contemporary multidomain core network paradigm to its limit. In the quest for new approaches that exploit recent developments in optical technology, a novel network architecture that obviates most of the expensive and loss-prone centralized all-optical switches is described in this work. It is based on clustered architecture for nodes in optical networks and features a reconciliation between dynamic resource allocation and guaranteed end-to-end network performance in a multidomain network. This article enhances the distributed, collision-free slot aggregation inside domains of clustered core nodes with dynamic switching of slots/frames between the domains. Thus, it can support dynamic sub-wavelength allocations between network domains, using standard burst-switching techniques. This extends the high efficiency and multiplexing gain into the inter-domain network even under highly bursty traffic. It features both low-cost optical add/drop edge nodes exploiting WDM transmission and agile and modular centralized electro-optical switches that are presented in conjunction with the overall network architecture. Its performance exhibits very low burst loss probability traded for a higher but tolerable and bounded delay.

This article takes a broad look at a variety of optical network technologies that have been developed over the past two decades and comments on why some were successful in the real world while others have yet to make it beyond research laboratories or paper publications. We describe each technology briefly and then offer possible explanations for its rapid or slow adoption by the industry

The field of optical communications continues to evolve to meet the ever increasing demands for capacity, flexibility, scalability, and security. In this second installment of the Optical Communications Networks Series in 2016, we have selected six contributions that address physical layer security in optical networks, resource optimization in cloud-based radio over fiber networks, transceiver configuration in flex-grid optical networks, control plane architecture in multi-domain elastic optical networks, cost assessment of FTTdp networks with G.Fast, and hybrid ROADM architectures for scalable C/DWDM metro networks. Diverse topics addressed in this issue are indicative of the pervasive role of optical communications technologies in modern communications networks

Reduction of installation and operational costs are currently the driving force behind the implementation of optical networks. 2D MEMS technology plays an important role in the development of these network systems with several applications, including optical cross-connects, protection switching, optical add-drop multiplexing and wavelength switching. The optical design and packaging technology that has been developed for 2D MEMS has resulted in a flexible platform that can be used to manufacture highly integrated fiber optic devices.

Over the past few years, micro-electromechanical systems (MEMS) have emerged as a leading technology for realizing transparent optical switching subsystems. MEMS technology allows high-precision micromechanical components such as micromirrors to be mass produced at low cost. These components can be precisely controlled to provide reliable high-speed switching of optical beams in free space. Additionally, MEMS offers solutions that are scalable in both port (fiber) count and the ability to switch large numbers of wavelengths (> 100) per fiber. To date, most of this interest has focused on two-dimensional and three-dimensional MEMS optical crossconnect architectures. We introduce a wavelength-selective switch based on one-dimensional MEMS technology and discuss its performance, reliability, and superior scaling properties. We also review several important applications for this technology in all-optical networks.

Continuous growth in demand for optical network capacity and the sudden maturation of WDM technologies have fueled the development of long-haul optical network systems that transport tens to hundreds of wavelengths per fiber, with each wavelength modulated at 10 Gb/s or more. Micro-electromechanical systems devices are recognized to be the enabling technologies to build the next-generation cost-effective and reliable high-capacity optical crossconnects. While the promises of automatically reconfigurable networks and bit-rate-independent photonic switching are bright, the endeavor to develop a high-port-count MEMS-based OXC involves overcoming challenges in MEMS design and fabrication, optical packaging, and mirror control. Due to the interdependence of many design parameters, manufacturing tolerances, and performance requirements, careful trade-offs must be made in MEMS device design as well as system design. We provide an overview of the market demand, various design trade-offs, and multidisciplinary system considerations for building reliable and manufacturable large MEMS-based OXCs.

Fiber-deep network topologies will allow broadband service delivery to become a reality. This article discusses optical technology being deployed by the cable industry to support broadband. Included is a discussion of the current network and plans for the next-generation network, driving fiber even closer to the-subscriber.

The explosion of the Internet has brought about an acute need for broadband communications, which can only be filled with optical networking. This in turn has resulted in an unprecedented interest in optical micro-electromechanical systems. Since the early days of fiber optics, it has been recognized that micro-optics was a fertile ground for the applications of MEMS. MEMS-based products offer substantial cost and performance advantages for optical networking applications in the area of switching fabrics, variable attenuators, tunable lasers, and other devices. This article provides a review of various types of MEMS technologies for optical networking applications.

The five articles chosen for this month's issue of the Optical Communications Series examine the higher-level protocols that are desperately needed as bandwidth continues its climb into the stratosphere. The proposals are not merely theoretical postulating, though, as the concepts presented herein are validated in real-world networks.

The articles in this series focus on the research going into higher-speed Ethernet. The articles are summarized here.

We present a broad review of the optical wireless field, from early experiments through to today's high-performance systems. Emphasis is placed on understanding the benefits and limitations of optical wireless, all of which ultimately define the applications. A variety of systems are examined, each incorporating a different technological solution to suit the particular application.

Optical fiber architectures of the future are envisioned to employ extensive splitting of optical signals, as well as multiple wavelength division multiplexing and demultiplexing. These architectures and networks have motivated the development and commercialization of today's planar passive components. Beyond and including these applications, the prospects for new and exciting uses of planar devices are excellent. Planar passive components already are providing such functions in what is known as fiber-in-the-loop (FITL) systems. These applications are discussed. >

Multi-quantum wells (MQW) show unique properties that ample exploitation of the optical fiber potential for telecommunications. The aim of this article is to show how MQW lasers can effectively match as well as forecast a variety of telecommunications needs, ranging from high performance fiber optic transmission systems to very low-cost applications, by exploiting the enormous flexibility and the peculiar physical properties of these artificial materials. After a description of fiber-optic transmission requirements, we will analyze in detail the operational and physical properties of semiconductor lasers, in order to point out where MQWs play their major role. The state of the art for these devices are illustrated, with a discussion of their experimental characteristics. >

The authors describe passive optical networks (PON), optical wavelength allocation, device and system technologies. Some examples of PON systems are given including SDM, WDM, FDM, and TCM. The authors go on to discuss optical modules LSI and optical amplifiers. The paper concludes with a discussion of upgrading PONs. >

In recent years, large-scale data centers have continued to be built out as the global Internet traffic has grown exponentially. These include both multi-tenant carrier-neutral ones and private data centers, and host many Internet application servers.

Reducing network protection costs, while maintaining an acceptable level of survivability, has become an important challenge for network planners and engineers. This article will review technology and architectures that may be used to implement cost effective survivable fiber networks for each transport layer, and discuss the interworking system between survivability mechanisms across different layers and associated open issues. Standards development, product availability and the current status of deployment will also be reviewed. The first section reviews a class of survivable fiber network architectures that has been deployed or is scheduled to be deployed. Next is a review of emerging technologies for these survivable architecture implementations. These emerging technologies include SONET, ATM, and passive optical technology. Finally the issue of multiple layer interworking on SONET/ATM networks is discussed. >

The three papers in this inaugural issue of the Optical Communications Series cover a broad range of optical communications topics.

The three articles in this special section cover a wide range of topics in optical communications. The articles are summarized here.

Storage area networks (SANs) are a promising technology to efficiently manage the ever-increasing amount of business data. Extending SANs over large distances becomes essential to facilitate data protection and sharing storage resources over large geographic distances. A WDM metropolitan ring network is examined as a suitable extension for SANs where it is shown that sectioning the ring can help deal with traffic asymmetry and hot node (SAN node on ring) scenarios. Several network architectures are studied: One of the architectures accommodates a single SAN and its mirror connected through a sectioning link. Another architecture accommodates two pairs of SANs and their mirrors with sectioning links connecting each pair. Issues investigated include impact of the number of co-existing IP (non SAN) nodes; traffic models: Poisson and self-similar; slotted regime: fixed-size (FS), variable-size (VS) and supersize (SS) slot schemes; MAC protocol design; handling traffic asymmetry and performance measures.

The present status and research trends in light sources, detectors, and various optical components are described, focusing mainly on those for single-mode fiber systems. Laser-diode and light-emitting-diode sources are described, and their problems and advantages are examined. The features of optical detectors, namely, avalanche and p-i-n photodiodes are discussed. A method of comparing the performance of optical receivers with different detectors, by examining the minimum detectable power at a specified error probability for the received pulses, is presented. Optical components such as optical filters, couplers, dividers, isolators, connectors, and switches are considered briefly. The potential of optoelectronic integrated circuits is discussed. >

The present state of optical coherent communication technologies, covering optical heterodyne/homodyne detection and optical frequency division multiplexing (optimal FDM), is discussed. Included is a description of the development history of coherent lightwave communication technology followed by a discussion of heterodyne detection for future long-haul high-speed systems. A description of optical coherent transmission systems using heterodyne/homodyne detection is presented along with a review of optical FDM technology and its applications. Future trends are examined. >

As fiber optics and optoelectronics technologies become, more and more, the technologies of choice for a wide range of communications transmission facility applications. It is useful to ask what role optoelectronic technologies can play in implementing communications switching facilities. What are the basic technologies which can be used to realize all-optical switching functions? How can these basic technologies be applied to implement various types of switching subsystem? What are the time frames anticipated for these various applications of photonic switching technology?

The ability of optical systems to provide the massive interconnections between processors required in most neural network models, which constitutes their chief advantage for such applications, is discussed, focusing on holography. Because of the essential nonlinearity of the holographic connections, nonlinear processing elements are needed to perform complex computations. The use of GaAs hybrid optoelectronic processing elements is examined. GaAs is an excellent material for this purpose, since it can be used to fabricate both fast electronic circuits and optical sources and detectors. It is shown how a complete hybrid neural computer can be implemented using available technology developed for conventional computing. An experimentally demonstrated network in which optics plays an even larger role is described. >

The purpose of this book is to give the novice and the practicing industrial and research experts a text which presents the overall state-of-the-art, as well as specific design details for complete systems. In addition, this book presents practical as well as theoretical descriptions of available fibers, cables, couplers, connectors, splices, light sources, modulators, photodetectors and repeaters. A book living up to this intent would be welcomed by the communications industry in general and by the fiber optic communications community in particular.