Programmable Integrated Photonics

This book provides the first comprehensive, up-to-date and self-contained introduction to the emergent field of Programmable Integrated Photonics (PIP). It covers both theoretical and practical aspects, ranging from basic technologies and the building of photonic component blocks, to designalternatives and principles of complex programmable photonic circuits, their limiting factors, techniques for characterization and performance monitoring/control, and their salient applications both in the classical as well as in the quantum information fields. The book concentrates and focusesmainly on the distinctive features of programmable photonics, as compared to more traditional ASPIC approaches.After some years during which the Application Specific Photonic Integrated Circuit (ASPIC) paradigm completely dominated the field of integrated optics, there has been an increasing interest in PIP. The rising interest in PIP is justified by the surge in a number of emerging applications that callfor true flexibility and reconfigurability, as well as low-cost, compact, and low-power consuming devices.Programmable Integrated Photonics is a new paradigm that aims at designing common integrated optical hardware configurations, which by suitable programming, can implement a variety of functionalities. These in turn can be exploited as basic operations in many application fields. Programmabilityenables, by means of external control signals, both chip reconfiguration for multifunction operation, as well as chip stabilization against non-ideal operations due to fluctuations in environmental conditions and fabrication errors. Programming also allows for the activation of parts of the chip,which are not essential for the implementation of a given functionality, but can be of help in reducing noise levels through the diversion of undesired reflections.

This book provides the first comprehensive, up-to-date and self-contained introduction to the emergent field of Programmable Integrated Photonics (PIP). It covers both theoretical and practical aspects, ranging from basic technologies and the building of photonic component blocks, to design alternatives and principles of complex programmable photonic circuits, their limiting factors, techniques for characterization and performance monitoring/control, and their salient applications both in the classical as well as in the quantum information fields. The book concentrates and focuses mainly on the distinctive features of programmable photonics, as compared to more traditional ASPIC approaches. After some years during which the Application Specific Photonic Integrated Circuit (ASPIC) paradigm completely dominated the field of integrated optics, there has been an increasing interest in PIP. The rising interest in PIP is justified by the surge in a number of emerging applications that call for true flexibility and reconfigurability, as well as low-cost, compact, and low-power consuming devices. Programmable Integrated Photonics is a new paradigm that aims at designing common integrated optical hardware configurations, which by suitable programming, can implement a variety of functionalities. These in turn can be exploited as basic operations in many application fields. Programmability enables, by means of external control signals, both chip reconfiguration for multifunction operation, as well as chip stabilization against non-ideal operations due to fluctuations in environmental conditions and fabrication errors. Programming also allows for the activation of parts of the chip, which are not essential for the implementation of a given functionality, but can be of help in reducing noise levels through the diversion of undesired reflections.

Silicon photonics is beginning to play an important role in driving innovations in communication and computation for an increasing number of applications, from health care and biomedical sensors to autonomous driving, datacenter networking, and security. In recent years, there has been a significant amount of effort in industry and academia to innovate, design, develop, analyze, optimize, and fabricate systems employing silicon photonics, shaping the future of not only Datacom and telecom technology but also high-performance computing and emerging computing paradigms, such as optical computing and artificial intelligence. Different from existing books in this area, Silicon Photonics for High-Performance Computing and Beyond presents a comprehensive overview of the current state-of-the-art technology and research achievements in applying silicon photonics for communication and computation. It focuses on various design, development, and integration challenges, reviews the latest advances spanning materials, devices, circuits, systems, and applications. Technical topics discussed in the book include: • Requirements and the latest advances in high-performance computing systems • Device- and system-level challenges and latest improvements to deploy silicon photonics in computing systems • Novel design solutions and design automation techniques for silicon photonic integrated circuits • Novel materials, devices, and photonic integrated circuits on silicon • Emerging computing technologies and applications based on silicon photonics Silicon Photonics for High-Performance Computing and Beyond presents a compilation of 19 outstanding contributions from academic and industry pioneers in the field. The selected contributions present insightful discussions and innovative approaches to understand current and future bottlenecks in high-performance computing systems and traditional computing platforms, and the promise of silicon photonics to address those challenges. It is ideal for researchers and engineers working in the photonics, electrical, and computer engineering industries as well as academic researchers and graduate students (M.S. and Ph.D.) in computer science and engineering, electronic and electrical engineering, applied physics, photonics, and optics.

Photonic technologies provide many unique physical advantages including ultra-high bandwidths, energy-efficient operations, and low coupling to environmental noise. Furthermore, recent advances in foundry-based manufacturing platforms have enabled the emerging field of integrated systems photonics. In contrast to their bulk optics counterparts, these systems can co-integrate dense ensembles of active photonic and electronic components on a single wafer with high phase stability and small device footprints. Initial demonstrations of each element in the integrated photonics stack-sources, processors, and detectors-motivate the development of wafer-scale photonic integrated circuit implementations, which are poised to form a key building block for fundamental advancements in computing, communications, and sensing. The first part of this thesis will discuss the development and early system-level demonstrations of linear programmable nanophotonic processors in the silicon-on-insulator platform for applications in quantum and classical machine learning and information processing. Using our developed processor architecture, we then present a nanophotonic Ising sampler for noise-assisted combinatorial optimization. Subsequently, we present a novel, foundry-compatible platform for integrating telecommunication-wavelength artificial atom quantum emitters directly in silicon photonic circuits. Finally, we report a capacity analysis of a structured interferometric receiver implemented with a silicon photonic processor for detection of optical signals in photon-sparse communication links.

This book sets out to build bridges between the domains of photonic device physics and neural networks, providing a comprehensive overview of the emerging field of "neuromorphic photonics." It includes a thorough discussion of evolution of neuromorphic photonics from the advent of fiber-optic neurons to today’s state-of-the-art integrated laser neurons, which are a current focus of international research. Neuromorphic Photonics explores candidate interconnection architectures and devices for integrated neuromorphic networks, along with key functionality such as learning. It is written at a level accessible to graduate students, while also intending to serve as a comprehensive reference for experts in the field.

With the slowing down of Moore's law and advances in nanophotonics, photonic information processing by photonic integrated circuits (PICs) has raised considerable interest to compete with electronic systems in energy-efficient high-throughput data processing, especially for emerging applications such as neuromorphic computing, quantum information, and microwave photonics. Success in these fields usually requires large-scale programmable PICs providing low-energy, compact, and high-speed building blocks with ultra-low insertion loss and precise control. Current programmable photonic systems, however, primarily rely on materials with weak and volatile thermo-optic or electro-optic modulation effects, leading to large footprints and high energy consumption. Alternatively, chalcogenide phase-change materials (PCMs) such as Ge2Sb2Te5 (GST) exhibit a substantial optical contrast in a static, self-holding fashion upon phase transitions, but the complexity of present PCM-integrated photonic applications is still limited mainly due to the poor optical or electrical actuation approaches. In this dissertation, by integrating GST on silicon photonic devices, a highly scalable nonvolatile integrated phase-change photonic platform with strong broadband attenuation modulation and optical phase modulation for programmable photonics is demonstrated. Utilizing a free-space pulsed laser, reversible all-optically quasi-continuous programming of the platform is performed, resulting in a nonvolatile multi-level microring-based photonic switch with a high extinction ratio up to 33 dB. To extend the platform to a multi-port broadband scheme, compact (~30 micrometers), low-loss (~1 dB), and broadband (over 30 nm with cross talk less than -10 dB) 1 x 2 and 2 x 2 switches are demonstrated based on the asymmetric directional coupler design. Electrical switching of the platform with different heaters including graphene, indium tin oxide, and silicon PIN diode heaters that allows large-scale integration and fast energy-efficient large-area switching is then modeled and compared, followed by the experiment with PIN diode heaters. Using GST-clad silicon waveguides and microring resonators, intrinsically compact and energy-efficient photonic switching units operated with low driving voltages, near-zero additional loss, and reversible switching with long endurance are obtained in a complementary metal-oxide-semiconductor (CMOS)-compatible process. This work paves the way for the very large-scale CMOS-integrated programmable electronic-photonic systems such as optical neural networks and general-purpose integrated photonic processors.

This open access book presents thirteen outstanding doctoral dissertations in Information Technology from the Department of Electronics, Information and Bioengineering, Politecnico di Milano, Italy. Information Technology has always been highly interdisciplinary, as many aspects have to be considered in IT systems. The doctoral studies program in IT at Politecnico di Milano emphasizes this interdisciplinary nature, which is becoming more and more important in recent technological advances, in collaborative projects, and in the education of young researchers. Accordingly, the focus of advanced research is on pursuing a rigorous approach to specific research topics starting from a broad background in various areas of Information Technology, especially Computer Science and Engineering, Electronics, Systems and Control, and Telecommunications. Each year, more than 50 PhDs graduate from the program. This book gathers the outcomes of the thirteen best theses defended in 2020-21 and selected for the IT PhD Award. Each of the authors provides a chapter summarizing his/her findings, including an introduction, description of methods, main achievements and future work on the topic. Hence, the book provides a cutting-edge overview of the latest research trends in Information Technology at Politecnico di Milano, presented in an easy-to-read format that will also appeal to non-specialists.

Integrated Photonics for Data Communications Applications reviews the key concepts, design principles, performance metrics and manufacturing processes from advanced photonic devices to integrated photonic circuits. The book presents an overview of the trends and commercial needs of data communication in data centers and high-performance computing, with contributions from end users presenting key performance indicators. In addition, the fundamental building blocks are reviewed, along with the devices (lasers, modulators, photodetectors and passive devices) that are the individual elements that make up the photonic circuits. These chapters include an overview of device structure and design principles and their impact on performance. Following sections focus on putting these devices together to design and fabricate application-specific photonic integrated circuits to meet performance requirements, along with key areas and challenges critical to the commercial manufacturing of photonic integrated circuits and the supply chains being developed to support innovation and market integration are discussed. This series is led by Dr. Lionel Kimerling Executive at AIM Photonics Academy and Thomas Lord Professor of Materials Science and Engineering at MIT and Dr. Sajan Saini Education Director at AIM Photonics Academy at MIT. Each edited volume features thought-leaders from academia and industry in the four application area fronts (data communications, high-speed wireless, smart sensing, and imaging) and addresses the latest advances. Includes contributions from leading experts and end-users across academia and industry working on the most exciting research directions of integrated photonics for data communications applications Provides an overview of data communication-specific integrated photonics starting from fundamental building block devices to photonic integrated circuits to manufacturing tools and processes Presents key performance metrics, design principles, performance impact of manufacturing variations and operating conditions, as well as pivotal performance benchmarks

This hands-on introduction to silicon photonics engineering equips students with everything they need to begin creating foundry-ready designs.