Springer Series in Photonics – serie

Nonlinear-optical (NLO) effects make possible devices that perform many functions, such as wavelength conversion and signal processing, while waveguides enable the devices to be both efficient and compact. This book presents a systematic description of the NLO field, with an emphasis on devices that use ferroelectric waveguides. The earlier chapters provide an introduction to the concepts of waveguides, NLO devices, coupled-mode formalism and phase matching. Then, various NLO interactions and the related characteristics are elucidated and the fabrication of waveguides and structures for quasi-phase matching are discussed. The volume culminates in a survey of device implementations and applications. In this respect, short-wavelength-generation devices, wavelength converters for WDM photonic networks, optical parametric amplifiers, and ultrafast signal processing devices are examined, including the most recent experimental results.

Photovoltaics, the direct conversion of sunlight to electricity, is now the fastest growing technology for electricity generation. Present "first generation" products use the same silicon wafers as in microelectronics. "Second generation" thin-films, now entering the market, have the potential to greatly improve the economics by eliminating material costs. Martin Green, one of the world’s foremost photovoltaic researchers, argues in this book that "second generation" photovoltaics will eventually reach its own material cost constraints, engendering a "third generation" of high performance thin-films. The book explores, self-consistently, the energy conversion potential of advanced approaches for improving photovoltaic performance and outlines possible implementation paths.

Photovoltaics, the direct conversion of sunlight to electricity, is now the fastest growing technology for electricity generation. Present "first generation" products use the same silicon wafers as in microelectronics. "Second generation" thin-films, now entering the market, have the potential to greatly improve the economics by eliminating material costs. Martin Green, one of the world’s foremost photovoltaic researchers, argues in this book that "second generation" photovoltaics will eventually reach its own material cost constraints, engendering a "third generation" of high performance thin-films. The book explores, self-consistently, the energy conversion potential of advanced approaches for improving photovoltaic performance and outlines possible implementation paths.

The information revolution of this century was brought about by photonics based on simple and common materials, such as glasses and semiconductors. Although semiconductors will continue to be of central importance in the present century, glasses will also be of great importance in future photonic devices since they have various advantages over other materials in homogene­ ity, transparency, easy fabrication and excellent solvent properties. This book focuses on selected topics which are new and of fundamental importance in the applications of active glasses in photonic devices based on our research concept called "induced structure. " The book originates from a final report of the Hirao Active Glass Project (HAP), Exploratory Re­ search for Advanced Technology (ERATO), Japan Science and Technology Corporation (JST). Most of the reports in the book concern glasses under the action of very strong electromagnetic fields such as that induced by femtosec­ ond lasers. They include creation of induced structures in glasses, analysis of induced structure, and some functional devices using active glasses. This book is designed to provide graduate students and new researchers with an introductory review of the recent developments in the field of photonic ma­ terials. The reader will benefit from an overview of the latest results in the applications of active glasses in photonic devices and from a wealth of knowl­ edge covering most basic solid-state physics, chemical physics, and electronic engineering.

Nonlinearities and optics, optoelectronics and fiber communications are discussed systematically in this book. In a unified theoretical treatment, the book addresses the three categories of materials: fibers, semiconductors, and nonlinear crystals. In each case emphasis is placed on the nonlinear character of their refractive indices and optical absorption. The text also gives an in-depth analysis of the uses and limitations of phontonic nonlinearities with regard to wavelength division multiplexing and high-speed fiber communications. It will be of interest to graduate students as well as researchers and engineers in the fields of nonlinear optics and optical communications.

Optical solitons in fibers are a beautiful example of how an abstract mathematical concept has had an impact on new information transmission technologies. The concept of all-optical data transmission with optical soliton systems is now setting the standard for the most advanced transmission systems. The book deals with the motion of light waves in optical fibers, the evolution of light wavepackets, optical information transfer, all-optical soliton transmission systems, the control of optical solitons, polarization effects, dispersion-managed solitons, WDM transmission, soliton lasers, all-optical switching and other applications. This book is a must for all researchers and graduate students active in the field of optical data transmission.

Nonlinear optical studies of periodic dielectric structures have blossomed in the past two decades. New fabrication techniques are producing fiber grating and multidimensional photonic crystals in materials where the refractive index can be varied by light pulses and beams. Gap solitons that can propagate at any velocity from zero to the speed of light and spatial solitons that prevent the diffractive spread of light in waveguide arrays are two examples of the new phenomena described in this book. Microstructured optical fibers allow control of the guided mode dispersion for broadband light generation and new soliton phenomena. Many new materials and structures are being developed that will impact new optical devices with applications in optical communications and optical data processing. All the above topics are addressed in detail in this book.

The development of clean energy resources as alternatives to oiI has become one of the most important challenges for modern science and technology. The obvious motivation for these efforts is to reduce the air polIution resulting from the mass consumption of fossil fuels and to protect the ecological cycles of the biosystems on Earth. Analyses of future energy usage envision that the energy structure in the 21st century will be characterized as a "Best Mix Age" involving different renewable energy forms. Among the wide variety of renewable energy projects in progress, photo­ voltaics is the most promising as a future energy technology. It is pollution­ free and abundantly available everywhere in the world, even in space, and can also operate with diffuse light. However, a major barrier impeding the devel­ opment of large-scale bulk power applications of photovoltaic systems is the high price of solar cell modules. Therefore, reduction of the costs of solar celIs is of prime importance. To achieve this objective, tremendous R&D efforts have been made over the past two decades in a wide variety of technical fields ranging from solar-cell materials, cell structure, and mass production pro­ cesses to the photovoltaic systems themselves. As the result, about an order of magnitude cost reduction has been achieved in the past 10 years.

This book gives the first unified presentation of the physics and applications of optoelectronic devices. It covers the devices whose operation relies on the properties of quantum wells and fiber optics as well as their applications for optical communications and optical signal processing. The reader will benefit from a comprehensive mathematical treatment and from a state of the art presentation of the latest results in applied optoelectronics and semiconductor physics. The two different and complementary physical theories for describing optoelectronic devices, namely the electromagnetic field theory and quantum mechanics, are treated together in a combined manner, such that links and analogies are made apparent wherever possible.

Modern communication technologies have revolutionized society and econ­ omy on a global scale, and progress in this field is still breathtaking. Among the crucial features of these developments is the possibility to transmit/receive ever-increasing bit rates at lower and lower cost. This is due to some ex­ tent to improved electronics, but it is much more due to the capabilities of opticaL fibre-based communication systems. Optical communication tech­ nologies were initially introduced in order to improve traditional information exchange, but they have recently become a key prerequisite for the tremen­ dous growth in internet traffic, and optical technologies will be even more important in enabling and supporting the future expansion of internet traffic with annual growth rates forecast at 100%-200%. It is the purpose of the present book to describe the enabling components of optical communication systems, in particular their fundamentals, principles and current status, as well as the potential for future developments. Following such a scheme, it is the editors' hope that this book will not only attract the attention of experts already working in the field, but be, at least, likewise directed to interested newcomers. The book is organized into eleven chapters addressing the essential optical and optoelectronic components which form the hardware basis of today's, and most likely of future, optical networks.

The quantum statistical properties of light generated in a semiconductor laser and a light-emitting diode (LED) have been a ?eld of intense research for more than a decade. This research monograph discusses recent research activities in nonclassical light generation based on semiconductor devices, performed mostly at Stanford University. When a semiconductor material is used as the active medium to generate photons, as in semiconductor lasers and LEDs, the ?ow of carriers (electrons andholes)isconvertedintoa?owofphotons. Providedthattheconversionis fast and e?cient, the statistical properties of the carriers (“pump noise”) can be transferred to the photons; if pump noise can be suppressed to below the shot noise value, the noise in the photon output can also be suppressed below thePoissonlimit. Sinceelectronsandholesarefermionsandhavecharges,the statisticalpropertiesoftheseparticlescanbesigni?cantlydi?erentfromthose of photons if the structure of the light-emitting device is properly designed to provide interaction between these particles. There has been a discrepancy between the theoretical understanding and experimental observation of noise in a macroscopic resistor until very - cently. The dissipation that electrons experience in a resistor is expected to accompany the ?uctuation due to partition noise, leading to shot noise in the large dissipation limit as is the case with photons. Experimental observation shows that thermal noise, expected only in a thermal-equilibrium situation (zero-bias condition), is the only source of noise featured by a resistor, - dependent of the current.

The vertical cavity surface emitting laser (VCSEL) is a relatively new se- conductor laser device, especially applicable to ?ber-optic networks in the 21st century. About 25 years have passed since its invention, and devices for Gigabit Ethernet are now being mass-produced. It is expected that VCSELs will open up a new era of very-high-speed ?ber-optic networks and a wide range of application areas. VCSEL have many advantages, such as: (i) monolithic and high-yield f- rication;(ii)extremelylowthresholdandsmallpowerconsumption;(iii)hi- speedmodulationcapabilityatlowdrivingcurrentlevels;(iv)easypackaging, and so on. The emission spectra have been extended from 850nm toward the visible and infrared regions. We can expect reasonably high-power output, enough for most applications, and extremely high powers in some engineered arrayed devices. This book project was initiated to provide important information on VCSELs, edited by Prof. Herbert Li. Very regrettably, while editing this book he passed away. After some time, the present editor succeeded him. Due to this reason the publication of this book was delayed, and the editor would like to thank the contributors for their patience. This book includes the basic concepts, device technology, and application areas of VCSELs, and can be read not only by scientists and engineers in the ?eld, but also by graduate course students who wish to start their research or to get an introduction to the vast knowledge on semiconductor lasers.

Nonlinear-optical (NLO) effects make possible devices that perform many functions, such as wavelength conversion and signal processing, while waveguides enable the devices to be both efficient and compact. This book presents a systematic description of the NLO field, with an emphasis on devices that use ferroelectric waveguides. The earlier chapters provide an introduction to the concepts of waveguides, NLO devices, coupled-mode formalism and phase matching. Then, various NLO interactions and the related characteristics are elucidated and the fabrication of waveguides and structures for quasi-phase matching are discussed. The volume culminates in a survey of device implementations and applications. In this respect, short-wavelength-generation devices, wavelength converters for WDM photonic networks, optical parametric amplifiers, and ultrafast signal processing devices are examined, including the most recent experimental results.

The information revolution of this century was brought about by photonics based on simple and common materials, such as glasses and semiconductors. Although semiconductors will continue to be of central importance in the present century, glasses will also be of great importance in future photonic devices since they have various advantages over other materials in homogene­ ity, transparency, easy fabrication and excellent solvent properties. This book focuses on selected topics which are new and of fundamental importance in the applications of active glasses in photonic devices based on our research concept called "induced structure. " The book originates from a final report of the Hirao Active Glass Project (HAP), Exploratory Re­ search for Advanced Technology (ERATO), Japan Science and Technology Corporation (JST). Most of the reports in the book concern glasses under the action of very strong electromagnetic fields such as that induced by femtosec­ ond lasers. They include creation of induced structures in glasses, analysis of induced structure, and some functional devices using active glasses. This book is designed to provide graduate students and new researchers with an introductory review of the recent developments in the field of photonic ma­ terials. The reader will benefit from an overview of the latest results in the applications of active glasses in photonic devices and from a wealth of knowl­ edge covering most basic solid-state physics, chemical physics, and electronic engineering.

Nonlinearities and optics, optoelectronics and fiber communications are discussed systematically in this book. In a unified theoretical treatment, the book addresses the three categories of materials: fibers, semiconductors, and nonlinear crystals. In each case emphasis is placed on the nonlinear character of their refractive indices and optical absorption. The text also gives an in-depth analysis of the uses and limitations of phontonic nonlinearities with regard to wavelength division multiplexing and high-speed fiber communications. It will be of interest to graduate students as well as researchers and engineers in the fields of nonlinear optics and optical communications.

Optical solitons in fibers are a beautiful example of how an abstract mathematical concept has had an impact on new information transmission technologies. The concept of all-optical data transmission with optical soliton systems is now setting the standard for the most advanced transmission systems. The book deals with the motion of light waves in optical fibers, the evolution of light wavepackets, optical information transfer, all-optical soliton transmission systems, the control of optical solitons, polarization effects, dispersion-managed solitons, WDM transmission, soliton lasers, all-optical switching and other applications. This book is a must for all researchers and graduate students active in the field of optical data transmission.

Nonlinear optical studies of periodic dielectric structures have blossomed in the past two decades. New fabrication techniques are producing fiber grating and multidimensional photonic crystals in materials where the refractive index can be varied by light pulses and beams. Gap solitons that can propagate at any velocity from zero to the speed of light and spatial solitons that prevent the diffractive spread of light in waveguide arrays are two examples of the new phenomena described in this book. Microstructured optical fibers allow control of the guided mode dispersion for broadband light generation and new soliton phenomena. Many new materials and structures are being developed that will impact new optical devices with applications in optical communications and optical data processing. All the above topics are addressed in detail in this book.

The development of clean energy resources as alternatives to oiI has become one of the most important challenges for modern science and technology. The obvious motivation for these efforts is to reduce the air polIution resulting from the mass consumption of fossil fuels and to protect the ecological cycles of the biosystems on Earth. Analyses of future energy usage envision that the energy structure in the 21st century will be characterized as a "Best Mix Age" involving different renewable energy forms. Among the wide variety of renewable energy projects in progress, photo­ voltaics is the most promising as a future energy technology. It is pollution­ free and abundantly available everywhere in the world, even in space, and can also operate with diffuse light. However, a major barrier impeding the devel­ opment of large-scale bulk power applications of photovoltaic systems is the high price of solar cell modules. Therefore, reduction of the costs of solar celIs is of prime importance. To achieve this objective, tremendous R&D efforts have been made over the past two decades in a wide variety of technical fields ranging from solar-cell materials, cell structure, and mass production pro­ cesses to the photovoltaic systems themselves. As the result, about an order of magnitude cost reduction has been achieved in the past 10 years.

This book gives the first unified presentation of the physics and applications of optoelectronic devices. It covers the devices whose operation relies on the properties of quantum wells and fiber optics as well as their applications for optical communications and optical signal processing. The reader will benefit from a comprehensive mathematical treatment and from a state of the art presentation of the latest results in applied optoelectronics and semiconductor physics. The two different and complementary physical theories for describing optoelectronic devices, namely the electromagnetic field theory and quantum mechanics, are treated together in a combined manner, such that links and analogies are made apparent wherever possible.

The vertical cavity surface emitting laser (VCSEL) is a relatively new se- conductor laser device, especially applicable to ?ber-optic networks in the 21st century. About 25 years have passed since its invention, and devices for Gigabit Ethernet are now being mass-produced. It is expected that VCSELs will open up a new era of very-high-speed ?ber-optic networks and a wide range of application areas. VCSEL have many advantages, such as: (i) monolithic and high-yield f- rication;(ii)extremelylowthresholdandsmallpowerconsumption;(iii)hi- speedmodulationcapabilityatlowdrivingcurrentlevels;(iv)easypackaging, and so on. The emission spectra have been extended from 850nm toward the visible and infrared regions. We can expect reasonably high-power output, enough for most applications, and extremely high powers in some engineered arrayed devices. This book project was initiated to provide important information on VCSELs, edited by Prof. Herbert Li. Very regrettably, while editing this book he passed away. After some time, the present editor succeeded him. Due to this reason the publication of this book was delayed, and the editor would like to thank the contributors for their patience. This book includes the basic concepts, device technology, and application areas of VCSELs, and can be read not only by scientists and engineers in the ?eld, but also by graduate course students who wish to start their research or to get an introduction to the vast knowledge on semiconductor lasers.

Modern communication technologies have revolutionized society and econ­ omy on a global scale, and progress in this field is still breathtaking. Among the crucial features of these developments is the possibility to transmit/receive ever-increasing bit rates at lower and lower cost. This is due to some ex­ tent to improved electronics, but it is much more due to the capabilities of opticaL fibre-based communication systems. Optical communication tech­ nologies were initially introduced in order to improve traditional information exchange, but they have recently become a key prerequisite for the tremen­ dous growth in internet traffic, and optical technologies will be even more important in enabling and supporting the future expansion of internet traffic with annual growth rates forecast at 100%-200%. It is the purpose of the present book to describe the enabling components of optical communication systems, in particular their fundamentals, principles and current status, as well as the potential for future developments. Following such a scheme, it is the editors' hope that this book will not only attract the attention of experts already working in the field, but be, at least, likewise directed to interested newcomers. The book is organized into eleven chapters addressing the essential optical and optoelectronic components which form the hardware basis of today's, and most likely of future, optical networks.

The quantum statistical properties of light generated in a semiconductor laser and a light-emitting diode (LED) have been a ?eld of intense research for more than a decade. This research monograph discusses recent research activities in nonclassical light generation based on semiconductor devices, performed mostly at Stanford University. When a semiconductor material is used as the active medium to generate photons, as in semiconductor lasers and LEDs, the ?ow of carriers (electrons andholes)isconvertedintoa?owofphotons. Providedthattheconversionis fast and e?cient, the statistical properties of the carriers (“pump noise”) can be transferred to the photons; if pump noise can be suppressed to below the shot noise value, the noise in the photon output can also be suppressed below thePoissonlimit. Sinceelectronsandholesarefermionsandhavecharges,the statisticalpropertiesoftheseparticlescanbesigni?cantlydi?erentfromthose of photons if the structure of the light-emitting device is properly designed to provide interaction between these particles. There has been a discrepancy between the theoretical understanding and experimental observation of noise in a macroscopic resistor until very - cently. The dissipation that electrons experience in a resistor is expected to accompany the ?uctuation due to partition noise, leading to shot noise in the large dissipation limit as is the case with photons. Experimental observation shows that thermal noise, expected only in a thermal-equilibrium situation (zero-bias condition), is the only source of noise featured by a resistor, - dependent of the current.