Download or read book Intra chip Free space Optical Interconnect written by Berkehan Ciftcioglu and published by . This book was released on 2012 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The number of cores and their performance in microprocessors continue to increase with CMOS technology scaling. Communications between the processor cores and memory/processor interfaces will demand increasingly larger bandwidth, lower latency, and better signal integrity. A fundamental paradigm change therefore is required for intra- and inter-chip interconnects. Optical interconnects exhibit inherent advantages in bandwidth, loss, and delay compared to the conventional copper wire based electrical interconnects, and will potentially generate significant performance gains and energy savings in future microprocessors. Currently, the on-chip optical interconnect schemes already proposed utilize circuit switching using wavelength division multiplexing (WDM) or all-optical packet switching, all based on planar optical waveguides and related photonic devices such as microrings. These proposed approaches pose signicant challenges in latency, energy effciency, integration, and scalability. This thesis presents a new alternative approach by utilizing free-space optics. This 3-D integrated intra-chip free-space optical interconnect (FSOI) leverages mature photonic devices such as integrated lasers, photodiodes, microlenses and mirrors. It takes full advantages of the latest developments in 3-D integration technologies. This interconnect system provides point-to-point free-space optical links between any two communication nodes to construct an all-to-all intra-chip communication network with little or no arbitration. Therefore, it has significant networking advantages over conventional electrical and waveguide-based optical interconnects. FSOI eliminates the delays and energy consumption associated with packet switching, routing, and buffering of the conventional electrical and other optical networks, hence reducing the idling time of cores during data package transmission, which is the major bottleneck in the real-world performance of multi-core processors. FSOI also reduces the inter- connect loss and provides no bandwidth degradation for long distance transmission, achieving large bandwidth density. It eliminates the losses associated with waveguide crossings in large-scale systems and reduces the routing complexity significantly. In addition, it eliminates the crosstalk between long waveguides, improving the signal integrity. Finally, improved signal integrity of FSOI simplifies the electronics into conventional transceivers and eliminates the need for advanced signal processing techniques or equalization. Overall, the proposed FSOI system can achieve low latency and high energy efficiency without sacrificing bandwidth density. An FSOI system is evaluated based on the real device parameters, predictive technology models and International Roadmap of Semiconductor's predictions. A single FSOI link achieves 10-Gbps data rate with 0.5-pJ/bit energy efficiency and less than 10 -12 bit-error-rate (BER). A system using this individual link can provide scalability up to 36 nodes, providing 10-Tbps aggregate bandwidth. A comparison analysis performed between a WDM-based waveguide interconnect system and the proposed FSOI system shows that FSOI achieves better energy efficiency than the WDM one as the technology scales. Similarly, network simulation on a 16-core microprocessor using the proposed FSOI system instead of mesh networks has been shown to speed up the system by 12% and reduce the energy consumption by 33%. As a part of the development of a 3-D integrated FSOI system, operating at 850 nm with a 10-Gbps data rate per optical link, the photonics devices and optical components are individually designed and fabricated. The photodiodes (PDs) are designed to have large area for efficient light coupling and low capacitance to achieve large bandwidth, while achieving reasonably high responsivity. A metal-semiconductor-metal (MSM) structure is chosen over p-i-n ones to reduce parasitic capacitance per area, to allow less stringent microlens-to-PD alignment for efficient light coupling with a large bandwidth. A novel MSM germanium PD is implemented using an amorphous silicon (a-Si) layer on top of the undoped germanium substrate, serving as a barrier enhancement layer, mitigating the low Schottky barrier height for holes due to fermi level pinning and a surface passivation layer, preventing charge accumulation and image force lowering of the barrier. Therefore, the dark current is reduced and low-frequency gain is eliminated. The PDs achieve a 13-GHz bandwidth with a 0.315-A/W responsivity and a 1.7-nA[mu]m2 dark current density. The microlenses are fabricated on a fused silica substrate based on the photoresist melt-and-reflow technique, followed by dry etching into fused silica substrate. The measured focal length of a 220-[mu]m aperture size microlens is 350-[mu]m away from the backside of the substrate. The vertical-cavity surface-emitting lasers (VCSELs) are fabricated on a commercial molecular beam epitaxially (MBE) grown GaAs wafer. The fabricated 8-[mu]m aperture size VCSEL can achieve 0.65-mW optical power at a 1.5-mA forward bias current with a threshold current of 0.48 mA and a 0.67-A/W slope efficiency. Three prototypes are implemented via integrating the individually fabricated components using non-conductive epoxy and wirebonding. The first prototype, built on a printed circuit board (PCB) using commercial VCSEL arrays, achieves a 5-dB transmission loss and less than -30-dB crosstalk at 1-cm distance with a small-signal bandwidth of 10 GHz, limited by the VCSEL. The second board-level prototype uses all fabricated components integrated on a PCB. The prototype achieves a 9-dB transmission loss at 3-cm distance and a 4.4-GHz bandwidth. The chip-level prototype is built on a germanium carrier with integrated MSM Ge PDs, microlenses on fused silica and VCSEL chip on GaAs substrates. The prototype achieves 4-dB transmission loss at 1 cm and 3.3-GHz bandwidth, limited by commercial VCSEL bandwidth"--Leaves vi-viii.

Download or read book Multi scale Free space Optical Interconnects for Intrachip Global Communications written by Michael J. McFadden and published by . This book was released on 2005 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Integrated Silicon Photonic Optical Phased Array for Free space Optical Interconnect written by Francis A. Smith and published by . This book was released on 2019 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Integrated optical phased arrays (OPAs) are rapidly becoming one of the most promising technologies for future light detection and ranging (LIDAR) applications, thanks to their advantages in size, weight, and power consumption as compared to conventional solutions. Large-scale OPAs can leverage high integration densities of electronic-photonic integrated circuit technology to generate finer beamwidth, better beamsteering control, and higher optical power. Free-space optical interconnects (FSOI) are emerging as an attractive alternative to planar electrical interconnects for inter- and intra-chip data communications. By leveraging the third dimension above the chip surface, FSOI solutions can offer higher bandwidth density compared to on-chip, waveguide-based solutions. Through 3-D integration, low cost, CMOS-compatible, silicon photonic FSOI systems for high performance data center communications are within reach. The versatility of integrated OPAs can address the accurate alignment requirements of such systems to ensure robust link performance. At optical frequencies, the conventional design of phased arrays relies on the Finite-Difference Time Domain (FDTD) method. The FDTD method explicitly calculates the evolution of the array pattern from a finely discretized spatial representation of the entire array over a short time scale. Thus, computation accuracy is directly traded for simulation time. In addition, the modeling techniques to manage this tradeoff do not accommodate asymmetric arrays or allow array analysis at the system level. In this work, I present an OPA circuit design based on the synthesis method, which significantly relaxes the computational cost, time, and accuracy tradeoffs of OPA design at optical frequencies by using the radiation pattern of a single emitter element to synthesize that of the whole array. Instead of modeling an entire emitter array using the FDTD method, the synthesis approach requires only a single emitter to be simulated using 3-D FDTD. A design flow based on phased array synthesis allows accurate and robust modeling of arbitrary 1-D and 2-D OPAs, and enables optimization of device parameters and array coefficients across the device and system levels. OPAs serving FSOI and LIDAR applications require scalable architectures, and full phase control for 2-D, grating-lobe free beamsteering. 2-D phased array beamsteering can be efficiently achieved with 2-D apertures. However, significant design challenges emerge when 2-D apertures are scaled. The number of individually addressable emitters within a 2-D aperture is limited by the number of waveguides that can be interwoven between the emitters. As the emitter pitch is increased to accommodate the waveguides, the grating lobe pitch decreases, and the field-of-view of the array is reduced. Furthermore, independent phase control of each emitter is necessary to maximize beamsteering range. For each emitter, a corresponding phase shifter is required. Thus, power consumption scales with the number of emitters within the aperture. A non-uniform distribution of emitters in a sparse array configuration can relax the design tradeoffs of scaling a 2-D aperture. In an optimized sparse array, the beamforming performance of the uniform array is preserved with significantly fewer emitters. Thus, fewer phase shifters are required and beamsteering power consumption is reduced. However, there is no closed-form solution to guide the optimization of a 2-D sparse aperture. Conventional sparse aperture design relies on the genetic algorithm. The genetic algorithm numerically emulates the evolutionary behaviors of DNA: mutation, crossover, and natural selection. For large apertures at optical frequencies, the genetic algorithm quickly becomes computationally prohibitive when compounded with hundreds to thousands of iterations. In addition, the optimized layout of emitters follows the uniform grid of the reference array. Arrays with a non-grid geometry may possess desirable pattern properties. However, these potential solutions lie outside the solution space and are treated as outliers by the genetic algorithm. The phased array synthesis design flow is used to develop a new technique for sparse OPA design by layout-constrained, array factor (LCAF) optimization. Instead of evaluating a large set of potential solutions, the LCAF method reduces the sparse optimization problem to three fundamental arrays, and leverages a triangular array geometry to achieve a scalable OPA aperture. The triangular array is distributed in a diagonally asymmetric configuration to increase waveguide routing area, and preserve the beamforming properties of an equivalent dense array. This diagonally asymmetric array geometry is designed to potentially increase orthogonal free-space optical beam steering range compared to conventional rectangular grid OPA geometries. The synthesis method is used to develop an OPA chip prototype in a standard silicon photonic technology. A technique is developed to leverage the natural static bias of the optical waveguide channels to reduce the power required for beamsteering control. Further, multi-function optical beam control is explored through subarray beam splitting. The fabricated chip prototype is packaged and tested in a custom free-space imaging test bench. A closed-loop, component-to-system optimization is used in both circuit design and testing. The measured beamwidth of the sparse OPA is 2.13 degrees in phi and 0.67 degrees in theta. The measured grating lobe free beamsteering range in phi is 20 degrees, and in theta is 24 degrees. The measurement results agree with the simulations and are successfully verified by the design"--Pages x-xii

Download or read book Optical Interconnects written by Ray T. Chen and published by Springer Nature. This book was released on 2022-05-31 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes fully embedded board level optical interconnect in detail including the fabrication of the thin-film VCSEL array, its characterization, thermal management, the fabrication of optical interconnection layer, and the integration of devices on a flexible waveguide film. All the optical components are buried within electrical PCB layers in a fully embedded board level optical interconnect. Therefore, we can save foot prints on the top real estate of the PCB and relieve packaging difficulty reduced by separating fabrication processes. To realize fully embedded board level optical interconnects, many stumbling blocks need to be addressed such as thin-film transmitter and detector, thermal management, process compatibility, reliability, cost effective fabrication process, and easy integration. The material presented eventually will relieve such concerns and make the integration of optical interconnection highly feasible. The hybrid integration of the optical interconnection layer and electrical layers is ongoing.

Download or read book Optical Wireless Communications written by Murat Uysal and published by Springer. This book was released on 2016-08-25 with total page 639 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on optical wireless communications (OWC), an emerging technology with huge potential for the provision of pervasive and reliable next-generation communications networks. It shows how the development of novel and efficient wireless technologies can contribute to a range of transmission links essential for the heterogeneous networks of the future to support various communications services and traffic patterns with ever-increasing demands for higher data-transfer rates. The book starts with a chapter reviewing the OWC field, which explains different sub-technologies (visible-light, ultraviolet (UV) and infrared (IR) communications) and introduces the spectrum of application areas (indoor, vehicular, terrestrial, underwater, intersatellite, deep space, etc.). This provides readers with the necessary background information to understand the specialist material in the main body of the book, which is in four parts. The first of these deals with propagation modelling and channel characterization of OWC channels at different spectral bands and with different applications. The second starts by providing a unified information-theoretic treatment of OWC and then discusses advanced physical-layer methodologies (including, but not limited to: advanced coding, modulation diversity, cooperation and multi-carrier techniques) and the ultimate limitations imposed by practical constraints. On top of the physical layer come the upper-layer protocols and cross-layer designs that are the subject of the third part of the book. The last part of the book features a chapter-by-chapter assessment of selected OWC applications. Optical Wireless Communications is a valuable reference guide for academic researchers and practitioners concerned with the future development of the world’s communication networks. It succinctly but comprehensively presents the latest advances in the field.

Download or read book Integrated Optical Interconnect Architectures for Embedded Systems written by Ian O'Connor and published by Springer Science & Business Media. This book was released on 2012-11-07 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a broad overview of current research in optical interconnect technologies and architectures. Introductory chapters on high-performance computing and the associated issues in conventional interconnect architectures, and on the fundamental building blocks for integrated optical interconnect, provide the foundations for the bulk of the book which brings together leading experts in the field of optical interconnect architectures for data communication. Particular emphasis is given to the ways in which the photonic components are assembled into architectures to address the needs of data-intensive on-chip communication, and to the performance evaluation of such architectures for specific applications.

Download or read book VCSELs and Optical Interconnects written by Hugo Thienpont and published by SPIE-International Society for Optical Engineering. This book was released on 2003 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optical Interconnects written by Lorenzo Pavesi and published by Springer. This book was released on 2007-05-17 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical Interconnects provides a fascinating picture of the state of the art in optical interconnects and a perspective on what can be expected in the near future. It is composed of selected reviews authored by world leaders in the field, and these reviews are written from either an academic or industrial viewpoint. An in-depth discussion of the path towards fully-integrated optical interconnects in microelectronics is presented. This book will be useful not only to physicists, chemists, materials scientists, and engineers but also to graduate students who are interested in the fields of microelectronics and optoelectronics.

Download or read book Advanced Materials for Integrated Optical Waveguides written by Xingcun Colin Tong Ph.D and published by Springer Science & Business Media. This book was released on 2013-10-17 with total page 574 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive introduction to integrated optical waveguides for information technology and data communications. Integrated coverage ranges from advanced materials, fabrication, and characterization techniques to guidelines for design and simulation. A concluding chapter offers perspectives on likely future trends and challenges. The dramatic scaling down of feature sizes has driven exponential improvements in semiconductor productivity and performance in the past several decades. However, with the potential of gigascale integration, size reduction is approaching a physical limitation due to the negative impact on resistance and inductance of metal interconnects with current copper-trace based technology. Integrated optics provides a potentially lower-cost, higher performance alternative to electronics in optical communication systems. Optical interconnects, in which light can be generated, guided, modulated, amplified, and detected, can provide greater bandwidth, lower power consumption, decreased interconnect delays, resistance to electromagnetic interference, and reduced crosstalk when integrated into standard electronic circuits. Integrated waveguide optics represents a truly multidisciplinary field of science and engineering, with continued growth requiring new developments in modeling, further advances in materials science, and innovations in integration platforms. In addition, the processing and fabrication of these new devices must be optimized in conjunction with the development of accurate and precise characterization and testing methods. Students and professionals in materials science and engineering will find Advanced Materials for Integrated Optical Waveguides to be an invaluable reference for meeting these research and development goals.

Download or read book A Free space Optical Solution for the On chip Global Interconnect Bottleneck Experimental Validation written by Rohit Nair and published by . This book was released on 2007 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the rigorous scaling down of CMOS critical dimensions, emerge several challenges that may signal the end of Moore's law. Although scaling results in devices that are faster and consume lower power, we will run into physical limits as miniaturization persists. It is now widely understood that on-chip global communication poses one such challenge due to issues such as the increasing power consumption and latency in the global wires, which are a direct consequence of scaling. We present optical interconnects as a candidate for relieving the performance bottleneck that metal wires will pose in the near future. A free-space optical inter-connection system has been proposed. The design and experimental validation of the free-space technique are presented.

Download or read book Technology Roadmap written by and published by . This book was released on 1998 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Self Organized 3D Integrated Optical Interconnects written by Tetsuzo Yoshimura and published by CRC Press. This book was released on 2021-03-09 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Currently, light waves are ready to come into boxes of computers in high-performance computing systems like data centers and super computers to realize intra-box optical interconnects. For inter-box optical interconnects, light waves have successfully been introduced by OE modules, in which discrete bulk-chip OE/electronic devices are assembled using the flip-chip-bonding-based packaging technology. OE modules, however, are not applicable to intra-box optical interconnects, because intra-box interconnects involve “short line distances of the cm–mm order” and “large line counts of hundreds-thousands.” This causes optics excess, namely, excess components, materials, spaces, fabrication efforts for packaging, and design efforts. The optics excess raises sizes and costs of intra-box optical interconnects enormously when they are built using conventional OE modules. This book proposes the concept of self-organized 3D integrated optical interconnects and the strategy to reduce optics excess in intra-box optical interconnects.

Download or read book Handbook of Optical Interconnects written by Shigeru Kawai and published by CRC Press. This book was released on 2018-10-03 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: As we reach the data transmission limits of copper wire and communications experts seek to bring the speed of long-haul fiber optics networks closer to access points, optical interconnects promise to provide efficient, high-speed data transmission for the next generation of networks and systems. They offer higher bit-rates, virtually no crosstalk, lower demands on power requirements and thermal management, and the possibility of two-dimensional channel arrays for chip-to-chip communication. The Handbook of Optical Interconnects introduces the systems and devices that will bring the speed and quality of optical transmission closer to the circuit board. Contributed by active experts, most from leading technology companies in the US and Japan, this outstanding handbook details various low-cost and small-size configurations, illustrates the discussion with more than 300 figures, and offers a look at the applications and future of this exciting and rapidly growing field. The book includes a detailed introduction to vertical cavity surface-emitting lasers (VCSELs); the use of optical interconnects in metropolitan, local-area, and access networks through FTTP (FTTH); and Jisso technologies, which are critical for developing low-cost, small-size modules. Driving down the size and cost of optical interconnects is vital for integrating these technologies into the network and onto microprocessors, and the Handbook of Optical Interconnects provides the knowledge and tools necessary to accomplish these goals.

Download or read book Micro optics VCSELs and Photonic Interconnects written by and published by . This book was released on 2004 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optoelectronic Interconnects written by and published by . This book was released on 1995 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optical Interconnects for Data Centers written by Tolga Tekin and published by Woodhead Publishing. This book was released on 2016-11-01 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current data centre networks, based on electronic packet switches, are experiencing an exponential increase in network traffic due to developments such as cloud computing. Optical interconnects have emerged as a promising alternative offering high throughput and reduced power consumption. Optical Interconnects for Data Centers reviews key developments in the use of optical interconnects in data centres and the current state of the art in transforming this technology into a reality. The book discusses developments in optical materials and components (such as single and multi-mode waveguides), circuit boards and ways the technology can be deployed in data centres. Optical Interconnects for Data Centers is a key reference text for electronics designers, optical engineers, communications engineers and R&D managers working in the communications and electronics industries as well as postgraduate researchers. Summarizes the state-of-the-art in this emerging field Presents a comprehensive review of all the key aspects of deploying optical interconnects in data centers, from materials and components, to circuit boards and methods for integration Contains contributions that are drawn from leading international experts on the topic

Download or read book Design Fabrication and Packaging of Free Space Optical Interconnects written by Wyatt Lee Hendrick and published by . This book was released on 2000 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: