دانلود کتاب امواج نوری در موجبرها و فضای آزاد

This book provides a thorough review of the multi-mode propagation inside the optical waveguides and free space. Multi-mode propagation in waveguides and free space has received particular attention recently due to its promising applications in various areas, such as communications and sensing. In the multi-mode waveguides and free space, the modes couple to each other due to the purposely engineered or random index fluctuations. The coupled modes interfere with one another and can be possibly exploited to form functional devices. It is revealed in this book that a universal coupled mode theory can be used to describe the mode propagation inside the waveguides and in free space. Stochastic analysis can be performed based on the theory and analytical solutions can be derived for the second-order and fourthorder moments to avoid time consuming Monte Carlo simulations. Mode generation and multiplexing devices are under consideration afterwards, which play key roles in mode division multiplexing systems. Finally, the concept is extended for the temporal domain and the four-dimensional space time. The book provides a comprehensive reviewof the rapidly expanding field of multimode transmission system and its basic physics, covers a vast array of special topics and applications related to the core technologies of the mode division multiplexing systems, and illustrates the wide use of the multi-mode propagation and transmission systems. The book is organized as follows. Chapter 1 “Multimode Propagation Fundamentals”. The chapter reviews the fundamental physics for multi-mode propagation inside waveguides and in free space. Coupled mode theory is derived. Multi-mode interference theory is revealed. Chapter 2 “Multimode Interference inWaveguides and Free Space”. The chapter deals with the modes in the waveguides or free space which propagates with different velocities and propagation constants. Interference is expected and can be used to design useful functional devices such as multi-mode interference couplers. Functional devices such as unitary transformers are designed based on the multi-mode interference concept. In free space, the multi-mode interference is described as the Talbot effect, which can be exploited to generate spatial modes. Chapter 3 “Coupled Mode Theory for Multi-mode Propagation”. The chapter introduces the coupled mode theory, which is a powerful tool for multi-mode propagation analysis. The coupled mode theory will be formulated both for the classic optics and quantum optics. While the coupled mode theory is a powerful tool for multimode propagation analysis in classic optics, quantum formulation of the multimode propagation is provided afterwards. Chapter 4“Wave Propagation in Multi-core Fibers”. The chapter studies themulticore fibers, which are considered as a special kind of multi-mode waveguide while the cores are closely coupled to each other and form the super-modes. The concept is discussed and analytical solutions are given for various multi-core fibers with different core arrangement. Chapter 5 “Random Coupling Theory for Multi-modeWaveguides and Free Space Propagation”. The chapter studies the random coupled mode theory, which has the coupling coefficients varies randomly and should be studied through the stochastic approach. The basic equations are given and the analytical results for the average value, as well as the second- and fourth-order moments are studied analytically as well. Chapter 6 “Mode Generation and Multiplexing for Multi-mode Waveguides and Free Space”. The chapter studies the mode generator and multiplexer, which are the key components for mode division multiplexing systems. The chapter discusses the novel ways to realize mode generators and multiplexers. Chapter 7 “Temporal Modes and Spatiotemporal Modes”. The chapter extends the theory of spatial beam propagation to the temporal domain, and the concept of temporal waveguides and temporal fractional Fourier transform are proposed. Afterwards, a temporal signal processing tool, i.e., a temporal diffractive deep neural network is proposed. The concept is extended beyond the spatial domain or the temporal domain, but the four-dimensional space time. A new class of spatialtemporal beam is discussed and a spatial-temporal diffractive deep neural network is proposed in the end. Finally, the authors would like to acknowledge the proofreading efforts of associate professor Jing Zheng from Shanghai Institute of Technology, as well as the contributions of the PhD students Tengyuan Liu and Chen Chen from Tongji University.