Detection Of Optical Signals

Detection of Optical Signals provides a comprehensive overview of important technologies for photon detection, from the X-ray through ultraviolet, visible, infrared to far-infrared spectral regions. It uniquely combines perspectives from many disciplines, particularly within physics and electronics, which are necessary to have a complete understanding of optical receivers. This interdisciplinary textbook aims to: Guide readers into more detailed and technical treatments of readout optical signals Give a broad overview of optical signal detection including terahertz region and two-dimensional material Help readers further their studies by offering chapter-end problems and recommended reading. This is an invaluable resource for graduate students in physics and engineering, as well as a helpful refresher for those already working with aerospace sensors and systems, remote sensing, thermal imaging, military imaging, optical telecommunications, infrared spectroscopy, and light detection.

This book is addressed to designers of photodetectors and photodetecting systems, designers of focal plane arrays, charge-coupled devices, specialists in IR technologies, designers of optoelectronic detecting, guiding and tracking systems, systems for IR direction finders, lidars, lightwave communication systems, IR imagers. All these specialists are united by one common purpose: they are all striving to catch the weakest possible optical signal. The most important characteristic of photosensitive devices is their detectivity, which determines the lowest level of optical signal they are able to detect above the noise level. These threshold characteristics define the most important tactical and technical parameters of the entire optoelectronic system, such as its range, resolution, precision. The threshold characteristics of optoelectronic system depend on many of its components; all designers agree, however, that the critically responsible part of the system is the photodetector [1]. By the end of the 1960s the physicists and the engineers were able to overcome many obstacles and to create photodetectors (at least single-element or few-element ones) which covered all the main optical bands (0. 4 . . . 2,2 . . . 3, 3 . . . 5,8 . . . 14 J. . Lm), carried out the detection almost without any loss (the quantum yield being as high as 0. 7 . . . 0. 9), and reduced the noise level to the lowest possible limit.

Textbook on the physical principles of optical fibers - for advanced undergraduates and graduates in physics or electrical engineering.

Fiber-optic communication systems have revolutionized our telecommunication infrastructures – currently, almost all telephone land-line, cellular, and internet communications must travel via some form of optical fibers. In these transmission systems, neither the phase nor frequency of the optical signal carries information – only the intensity of the signal is used. To transmit more information in a single optical carrier, the phase of the optical carrier must be explored. As a result, there is renewed interest in phase-modulated optical communications, mainly in direct-detection DPSK signals for long-haul optical communication systems. When optical amplifiers are used to maintain certain signal level among the fiber link, the system is limited by amplifier noises and fiber nonlinearities. Phase-Modulated Optical Communication Systems surveys this newly popular area, covering the following topics: - The transmitter and receiver for phase-modulated coherent lightwave systems - Method for performance analysis of phase-modulated optical signals - Direct-detection DPSK signal with fiber nonlinearities, degraded by nonlinear phase noise and intrachannel effects - Wavelength-division-multiplexed direct-detection DPSK signals - Multi-level phase-modulated optical signals, such as the four-phase DQPSK signal. Graduate students, professional engineers, and researchers will all benefit from this updated treatment of an important topic in the optical communications field.

These are exciting times for the field of optical imaging of brain function. Rapid developments in theory and technology continue to considerably advance understanding of brain function. Reflecting changes in the field during the past five years, the second edition of In Vivo Optical Imaging of Brain Function describes state-of-the-art techniques and their applications for the growing field of functional imaging in the live brain using optical imaging techniques. New in the Second Edition: Voltage-sensitive dyes imaging in awake behaving animals Imaging based on genetically encoded probes Imaging of mitochondrial auto-fluorescence as a tool for cortical mapping Using pH-sensitive dyes for functional mapping Modulated imaging Calcium imaging of neuronal activity using 2-photon microscopy Fourier approach to optical imaging Fully updated chapters from the first edition Leading Authorities Explore the Latest Techniques Updated to reflect continuous development in this emerging research area, this new edition, as with the original, reaches across disciplines to review a variety of non-invasive optical techniques used to study activity in the living brain. Leading authorities from such diverse areas as biophysics, neuroscience, and cognitive science present a host of perspectives that range from a single neuron to large assemblies of millions of neurons, captured at various temporal and spatial resolutions. Introducing techniques that were not available just a few years ago, the authors describe the theory, setup, analytical methods, and examples that highlight the advantages of each particular method.

This text treats the fundamentals of optical and infrared detection in terms of the behavior of the radiation field, the physical properties of the detector, and the statistical behavior of the detector output. Both incoherent and coherent detection are treated in a unified manner, after which selected applications are analyzed, following an analysis of atmospheric effects and signal statistics. The material was developed during a one-semester course at M.I.T. in 1975, revised and presented again in 1976 at Lincoln Laboratory, and rewritten for publication in 1977. Chapter 1 reviews the derivation of Planck's thermal radiation law and also presents several fundamental concepts used throughout the text. These include the three thermal distribution laws (Boltzmann, Fermi-Dirac, Bose Einstein), spontaneous and stimulated emission, and the definition and counting of electromagnetic modes of space. Chapter 2 defines and analyzes the perfect photon detector and calculates the ultimate sensitivity in the presence of thermal radiation. In Chapter 3, we turn from incoherent or power detection to coherent or heterodyne detection and use the concept of orthogonal spatial modes to explain the antenna theorem and the mixing theorem. Chapters 4 through 6 then present a detailed analysis of the sensitivity of vacuum and semiconductor detectors, including the effects of amplifier noise.

This book covers a wide range of technical issues relating to lightwave technologies using high coherence lightwaves. Electromagnetic wave communication started when the first wireless system was invented by Marconi in 1895. However, we had to wait about one hundred years to realize a similar technology in the lightwave frequency region. The invention of lasers in 1960 and two technology innovations in 1970 -low loss silica fiber and semiconductor lasers operating at room temperature - promoted the development of fiber-optic transmission systems. The deployment of high-speed long-haul fiber-optic transmission systems has led to the formation of domestic and international trunk networks. The installed fiber cables in local loop plants provide multimedia communication services including broadband video. However, present lightwave communication systems do not fully utilize the fruitful potential oflightwaves, namely the capacity of extremely high frequency electromagnetic information carrier waves. The frequency oflightwaves used for fiber-optic transmission is about 200 THz 14 (2 x 10 Hz), and the frequency bandwidth of the fiber low loss region is about 13 20 THz (2 x 10 Hz). Recent developments of narrow spectrum width semiconduc tor laser and planar optical waveguide devices offer us the possibilities for a new generation of lightwave-based communication systems. This book focuses on system aspects ofthe new generation lightwave communi cation technologies such as optical frequency division multiplexing and coherent detection. Chapter 1 overviews lightwave communication system technology.