Photonics

About: Photonics is a research topic. Over the lifetime, 37918 publications have been published within this topic receiving 797995 citations. The topic is also known as: optics and photonics.

Long-distance quantum communication with atomic ensembles and linear optics

Abstract: Quantum communication holds a promise for absolutely secure transmission of secret messages and faithful transfer of unknown quantum states. Photonic channels appear to be very attractive for physical implementation of quantum communication. However, due to losses and decoherence in the channel, the communication fidelity decreases exponentially with the channel length. We describe a scheme that allows to implement robust quantum communication over long lossy channels. The scheme involves laser manipulation of atomic ensembles, beam splitters, and single-photon detectors with moderate efficiencies, and therefore well fits the status of the current experimental technology. We show that the communication efficiency scale polynomially with the channel length thereby facilitating scalability to very long distances.

Terahertz semiconductor heterostructure laser

Abstract: Semiconductor devices have become indispensable for generating electromagnetic radiation in everyday applications. Visible and infrared diode lasers are at the core of information technology, and at the other end of the spectrum, microwave and radio-frequency emitters enable wireless communications. But the terahertz region (1-10 THz; 1 THz = 10(12) Hz) between these ranges has remained largely underdeveloped, despite the identification of various possible applications--for example, chemical detection, astronomy and medical imaging. Progress in this area has been hampered by the lack of compact, low-consumption, solid-state terahertz sources. Here we report a monolithic terahertz injection laser that is based on interminiband transitions in the conduction band of a semiconductor (GaAs/AlGaAs) heterostructure. The prototype demonstrated emits a single mode at 4.4 THz, and already shows high output powers of more than 2 mW with low threshold current densities of about a few hundred A cm(-2) up to 50 K. These results are very promising for extending the present laser concept to continuous-wave and high-temperature operation, which would lead to implementation in practical photonic systems.

Channel plasmon subwavelength waveguide components including interferometers and ring resonators

Abstract: Photonic components are superior to electronic ones in terms of operational bandwidth, but the diffraction limit of light poses a significant challenge to the miniaturization and high-density integration of optical circuits. The main approach to circumvent this problem is to exploit the hybrid nature of surface plasmon polaritons (SPPs), which are light waves coupled to free electron oscillations in a metal that can be laterally confined below the diffraction limit using subwavelength metal structures. However, the simultaneous realization of strong confinement and a propagation loss sufficiently low for practical applications has long been out of reach. Channel SPP modes--channel plasmon polaritons (CPPs)--are electromagnetic waves that are bound to and propagate along the bottom of V-shaped grooves milled in a metal film. They are expected to exhibit useful subwavelength confinement, relatively low propagation loss, single-mode operation and efficient transmission around sharp bends. Our previous experiments showed that CPPs do exist and that they propagate over tens of micrometres along straight subwavelength grooves. Here we report the design, fabrication and characterization of CPP-based subwavelength waveguide components operating at telecom wavelengths: Y-splitters, Mach-Zehnder interferometers and waveguide-ring resonators. We demonstrate that CPP guides can indeed be used for large-angle bending and splitting of radiation, thereby enabling the realization of ultracompact plasmonic components and paving the way for a new class of integrated optical circuits.

Silicon optical modulators

Abstract: Optical technology is poised to revolutionize short-reach interconnects. The leading candidate technology is silicon photonics, and the workhorse of such an interconnect is the optical modulator. Modulators have been improved dramatically in recent years, with a notable increase in bandwidth from the megahertz to the multigigahertz regime in just over half a decade. However, the demands of optical interconnects are significant, and many questions remain unanswered as to whether silicon can meet the required performance metrics. Minimizing metrics such as the device footprint and energy requirement per bit, while also maximizing bandwidth and modulation depth, is non-trivial. All of this must be achieved within an acceptable thermal tolerance and optical spectral width using CMOS-compatible fabrication processes. This Review discusses the techniques that have been (and will continue to be) used to implement silicon optical modulators, as well as providing an outlook for these devices and the candidate solutions of the future.

Fiber Bragg Gratings

Abstract: * Provides an overview of Fiber Bragg Gratings (FBGs), from fundamentals to applications* Evaluates the advantages and disadvantages of particular applications, methods and techniques* Contains new chapters on sensing, femtosecond laser writing of FBGs and poling of glass and optical fibers* Includes a special version of the photonic simulator PicWave(tm), allowing the reader to make live simulations of many of the example devices presented in the book This fully revised, updated and expanded second edition covers the substantial advances in the manufacture and use of FBGs in the years since the publication of the pioneering first edition It presents a comprehensive treatise on FBGs and addresses issues such as the merits of one solution over another; why particular fabrication methods are preferred; and what advantages a user may gain from certain techniques Beginning with the principles of FBGs, the book progresses to discuss photosensitization of optical fibers, Bragg grating fabrication and theory, properties of gratings, specific applications, sensing technology, glass poling, advances in femtosecond laser writing of Bragg gratings and FBG measurement techniques In addition to material on telecommunications usage of FBGs, application areas such as fiber lasers and sensors are addressed in greater detail This special version of Picwave is limited to modelling only the passive fibre devices covered in this book However the full PicWave package is capable of modelling other non-linear and active devices such as laser diodes and SOAs as discussed in Chapter 8 More information about PicWave can be found at wwwphotondcom/products/picwavehtm In addition to researchers, scientists, and graduate students, this book will be of interest to industrial practitioners in the field of fabrication of fiber optic materials and devices Raman Kashyap, Canada Research Chair holder on Future Photonics Systems, and Professor at cole Polytechnique, University of Montr al since 2003, has researched optical fibers and devices for over 30 years He pioneered the fabrication of FBGs and applications in telecommunications and photonics * Provides an overview of Fiber Bragg Gratings (FBGs), from fundamentals to applications* Evaluates the advantages and disadvantages of particular applications, methods and techniques* Contains new chapters on sensing, femtosecond laser writing of FBGs and poling of glass and optical fibers* Includes a special version of the photonic simulator PicWave(tm), allowing the reader to make live simulations of many of the example devices presented in the book