...Coupling losses between standard single-mode fibers and rectangular waveguides for integrated optics Lars O. Lierstuen and Aasmund Sv. Sudbø The butt-coupling loss between different tapered rectangular waveguides and a standard single-mode optical fiber has been calculated. Losses as low as 0.16 dB can be reached for waveguides with a refractive-index contrast in the range of 0.5% to 1.96%. The fabrication tolerances are such that practical devices with coupling losses below 0.25 dB are feasible. Key words: Coupling loss, optical waveguides, integrated optics. 1. Introduction In optical systems that contain integrated optical components, mode-field mismatch between the fundamental mode of the waveguides of an integrated optical circuit and the optical fiber that is connected to the circuit may cause unacceptable power losses. This problem becomes more important as the refractive-index contrast of the integrated optical waveguides, D, which is given by the core refractive index nco and the cladding refractive index ncl, D5 nco2 2 ncl2 2nco 2 < nco 2 ncl nco , 112 is increased. To achieve a good match to optical fibers, silica waveguides are usually designed to have D in the range 0.3–0.7%. Coupling loss as low as 0.05 dB has been reported for such waveguides.1 Increasing D, however, may be preferable because it makes a reduction of the size 1and hence the price2 of an optical component possible.2 The size reduction is mainly due to shorter coupling lengths...
Words: 3282 - Pages: 14
...result of respiration. The skeletal muscle is made of two different kinds of fibers: slow twitch (ST) and fast twitch (FT). Slow twitch fibers are mostly used in prolonged, because they are low and moderate the intensity activities. Slow Twitch fibers are more efficient at using oxygen to extend muscle contractions over a long time. As for the fast twitch fibers they use up more energy and the muscle fibers contract very fast. They are much better at generating short bursts of strengths and that slow. The fast twitch are usually used in short intense activities....
Words: 594 - Pages: 3
...ortamının indisine bağlıdır. Kırılma indisi optik-fiber içinde sabit değildir. Optik-fiber içinde ilerleyen ışığın dalga boyuna bağımlı olarak değişir. Dolayısı ile yayılma hızı dalga boyuna bağlı olup, bu bağımlılık dispersiyon olarak ifade edilir. Dispersiyon etkileri çok modlu fiberlerde karşılaştığımız bir sorun olup, tek modlu fiberlerde dikkate alınmaz. TR Modal Dispersion Modlar arası dispersiyon yüzünden oluşan pals genişlemesi, (bazen basitçe modal veya mod dispersiyonu denir) çok modlu bir fiber içindeki modlar arasındaki yayılma gecikme farklarından kaynaklanır. ispersion management is a somewhat wider term than dispersion compensation, even though both are often used in the same way. Strictly, dispersion compensation should be understood as a method for canceling the chromatic dispersion of some optical element(s), whereas dispersion management is more generally the use of tailored dispersion properties in order to enhance some function. Modal Dispersion Modal dispersion deals with the path (mode) of each light ray. As mentioned above, most transmitters emit many different modes. Some of these light rays will travel straight through the center of the fiber (axial mode) while others will repeatedly bounce off the cladding/core boundary to zigzag their way along the waveguide, as illustrated below. The modes that enter at sharp angles are called high-order modes. These modes take much longer to travel through the fiber than the low-order modes and therefore contribute...
Words: 722 - Pages: 3
...Introduction to Fiber Optics The equipment, tools and cabling that comprise a fiber optic link, how they work and their advantages over traditional copper. commspecial.com edu Guide Communications Specialties, Inc. is committed to increased education and knowledge in the Pro A/V and Broadcast industries. We hope that you enjoy reading – and learning! – with our eduGuide series of educational resources. For additional information on these and other industry related technologies, please visit us at commspecial.com today! ©2009 Communications Specialties, Inc. All Rights Reserved. Specifications, claims or other product information contained in this document are subject to change without notice. This document may not be reproduced, in whole or in part, without the express written consent of Communications Specialties, Inc., Fiberlink, Pure Digital Fiberlink, the starburst logo, Scan Do and Deuce are registered trademarks of Communications Specialties, Inc. CSI and the triangle designs are trademarks of Communications Specialties, Inc. October 8, 2009 Table of Contents A Brief Introduction ............................................................................................................ 2 Advantages of Fiber Optic Systems .............................................................................. 3 Optical Transmitters ........................................................................................................... 5 The Optical Fiber ............
Words: 5977 - Pages: 24
...INTRODUCTION 2.1 REPORT OUTLINE Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of light through an optical fiber. The light forms an electromagnetic carrier wave that is modulated to carry information. First developed in the1970s, fiber-optic communication systems have revolutionized the telecommunications industry and have played a major role in the advent of the Information Age. Because of its advantages over electrical transmission, optical fibers have largely replaced copper wire communications in core networks in the developed world. Optical fiber is used by many telecommunications companies to transmit telephone signals, Internet communication, and cable television signals....
Words: 7807 - Pages: 32
...Fiber Optics: The Super Highway of Information We live in an information age. Broadband is the foundation of economic growth and telecommunications is making its mark in all parts of the world. It is what enables the internet that drives e-commerce, education and universal access to information. Rapidly increasing communication density in this growing field and the ever increasing information flow is resulting in massive expansion in worldwide networks. The need for quick and reliable transmission and retrieval of ever increasing volumes of information over great distances is getting more and more important every day. This paper explains the history, the fiber optic theory, and the future of worldwide fiber optics networks already in progress. One would normally think that fiber optics is relatively new to this century, but looking back in history, there are many concepts which lead to the creation of fiber optics. The transition to optics concurred with the conversion from analog to digital transmission in the telephone network and with the growing necessity of computer data transmission. Long before fiber optics was first discovered, many signals were carried through a copper coaxial cable. Invented by Oliver Heaviside in 1880, copper conductors are used for mostly analog signals, such as high frequency radio waves, cable television signals, and power lines (Nahin 1988). He determined by wrapping an insular layer around a transmission line both improves the quality of...
Words: 2949 - Pages: 12
...INTRODUCTION OPTICAL FIBRE: Definition: An optical fiber (or optical fibre) is a flexible, transparent fiber made of a pure glass(silica).It functions as a waveguide, or light pipe, to transmit light between the two ends of the fiber. The field of applied science and engineering concerned with the design and application of optical fibers is known as fiber optics. Optical fibers are widely used in fiber-optic communications, which permits transmission over longer distances and at higher bandwidths (data rates) than other forms of communication. Fibers are used instead of metal wires because signals travel along them with less loss and are also immune to electromagnetic interference. How an Optical Fiber Works An Optical Fiber works on the principle of Total Internal Reflection. Light rays are reflected and guided down the length of an optical fiber. The acceptance angle of the fiber determines which light rays will be guided down the fiber. Types of fibre: Single mode OF:In single mode optical fibre only one mode of light is propagated.It is used for long distance application. DOF fibre:It is dispersion optimized single mode fiber and used for ultra long distance application. Multi Mode fibre:In multi mode the core size(50µm or 62.5 µm)is higher compare to single mode fibre and more than one mode of light can be propagated at a time.It is normally used for short distance application. Product Names of Fibres: 1. ON lite 2. PMD lite 3. BOW lite 4. DOF...
Words: 2476 - Pages: 10
......... ......... ........ ............ ................ 4 Standards........ ….... ….............. …........... …......... …........... ….......... .. 4 Historical Milestones........ …... …... …...... ….... …......... …....... …....... 4 Optical Networking why......... ….......... …..................... …................ …. 5 Principles and Operation............... …................. …........ ….............. …... 5-8 Single Mode Fiber............ …........................ ….................. …...... 6 Multimode Fiber................. ….................. ….............. …........ … 6-7 Optical Networking Tools.............. …............... …............. …............ ….. 8-10 Fiber Optic Splicers................. …............. ….... …........... …........ 8-9 Fiber Optic connectors.................. …............... …................. ….... 9 Fiber optic couplers........... …................. …............. …............ …. 9 Fiber Optic Transmitters................ ….................. …............ …...... 9 Fiber Optic Receivers............ ….................. …............ …..... ….... 10 Types Of Optical Networks.............. …........................... …............. …..... Optical Network Architecture............... …............... …............ ….......... ... Optical Networking vs Other Technologies................. …............ …......... Optical Networking Advantages........ …................ …................. ….. …. Optical...
Words: 3428 - Pages: 14
...cutting, alignment and guidance, and in surgery; the optical properties are exploited in holography, reading bar codes, and in recording and playing compact discs. 4. Output Pattern: aka NA of light source directly relates to the energy coupled into the core of the optical fiber. 5. Output Power: Amount of power a component, circuit or system can deliver to a load. 6. Modulation Speed: In fiber optics, modulation is associated with the telecommunications and data transport of digital information signals and analog audio/video signals, in which the digital/analog signal(s) are transmitted within another sine wave form known as a "passband". Common references for analog include pulse-code modulation (PCM), amplitude modulation (AM) and frequency modulation (FM). Digital modulation technologies are accomplished by "keying" methods: Phase-shift keying (PSK), Frequency-shift keying (FSK), Amplitude-shift keying (ASK) and Quadrature-amplitude modulation (QAM). 7. Core Diameter Mismatch: The central part of an optical fiber that provides the transmission region for an optical signal. The core is manufactured of an optically pure glass of a high refractive index surrounded by a lower refractive index cladding. Optical cores can range in size from 4.5...
Words: 1414 - Pages: 6
...experiment was to study the laws of reflection, refraction and total internal reflection, to measure the focal length of mirrors with convex and concave mirrors, and to measure the index of refraction of water. Theory: In this experiment, we learned that the angle of incidence θi is the angle that the incident ray makes in regards to the normal one. Also, the angle of reflection θr is the angle that the reflected ray produces from the normal one. Also, we discussed how the law of reflection is used to explain the behavior of the incident and reflected rays. According to Snell’s law, we observed that the incident ray, the reflected ray, and the normal line to the surface, all lie in the same plane and θi=θr. During the experiment we analyzed, the light striking the interface between two transparent materials and part of the light was reflected. The angle of the reflection equaled to the angle of incidence. The rest was passed along the interface and the ray entered that entered the second material was refracted. When light travels from medium #1, with a refractive index being n1, into the medium #2, with refractive index n2, the equation sinθ1= n2sinθ2. Lastly, we did a test that shows that when a light passes from a medium of large refractive index into one of small refractive index, the refracted ray it produces bends away from the normal because of the equation: n1>n2⇒sinθ1<sinθ2⇒ θ1<θ2 . Therefore, as the angle of incidence goes up, the angle...
Words: 1433 - Pages: 6
...avoiding rice consumption because rice is considered as hyperglycemic food (can raise blood glucose level quickly) and replacing it with tubers. Whereas rice has a range of Glycemic Index value (GI), from low to high GI depending on the species and varieties. Rices that raise blood glucose level quickly have high GI levels, whereas with low GI will raise blood glucose levels slowly. Glycemic Index (GI) The number listed next to each food is its glycemic index. This is a value obtained by monitoring a person’s blood sugar after eating the food. The value can vary slightly from person to person and from one type or brand of food and another. A noticeable difference is the GI rating of Special-K which produced considerably different results in tests in the US and Australia, most likely resulting from different ingredients in each location. Despite this slight variation, the index provides a good guide to which foods you should be eating and which foods to avoid. The glycemic index range is as follows: |Low GI = 55 or less | |Medium GI = 56 - 69 | |High GI = 70 or more | The glycemic index was researched by Sydney University in conjunction with the CSIRO, based on original research by the University of Toronto, Canada. Sydney University’s great glycemic index website is here http://www.glycemicindex.com/. Choosing low GI carbs - the...
Words: 1378 - Pages: 6
...Copper vs. Fiber Todd Gerger NT1310 Abstract In this paper we will be looking at the differences between Copper and Fiber optic cables. We will discuss the differences between the two and why many of the current networks in operation use fiber on the backbone between equipment and telecommunications rooms or enclosures. Copper vs. Fiber In the comparison between fiber and copper fiber, costs of the fiber cable has come down quite a bit. The cable itself has become easier to install as well since the invention of the flexible fiber which makes it easier to pull the cable through places. The flexible fiber has not become widely used vs. copper yet due to the need for the costs to come down for the connections, the NIC’s. the hub’s, routers and switches. Fiber Advantages The following advantages of fiber over other cabling systems are: (Oliviero 250) Immunity to electromagnetic interference (EMI), higher data rates, longer maximum distances, and better security. With copper cabling there is one common cabling problem they are susceptible to EMI. EMI is a stray electromagnetism that interferes with the signal. All electrical cables generate a magnetic field around their central axis. If you pass a metal conductor through a magnetic field an electrical field is generated in that conductor. When you place two cables next to one another EMI will cause cross-talk which is where signals from one cable is picked up on the other cable. Because fiber does not conduct electricity...
Words: 1089 - Pages: 5
...Final examination Theory 1. Explain the dispersion of light by a transparent dielectric material. The phenomen of dispersion is connected to the fact that the refractive index is dependent on the wavelength. Due to dispersion, the light waves from a complex radiation are bent by different angles as they enter a dispersive medium and they may be visualized separately. The index of refraction of a transparent dielectric medium is defined as the ratio of the speed of an electromagnetic wave in empty space to its speed in the medium. . It is a measure of the slowing factor for light traveling in that medium The refractive index can be expressed as a function of the electric and magnetic properties of the medium . For most of the materials that are transparent to visible light and . Hence the magnetic properties have a small effect on the light propagation. When an electromagnetic wave is incident on a medium, it electrically polarizes the molecules. This changes the value of which in its turn, determines the index of refraction. The process is wavelength dependent: different wavelengths will induce different polarizations of the molecules and, as a result, and will be different. So, the index of refraction changes with wavelength: The phenomenon described above is known as the dispersion of light. Equation is the dispersion relation. For most of the materials, decreases with the wavelength (see figure1). This phenomenon is known as normal dispersion...
Words: 7639 - Pages: 31
...communications link. • Enormous Bandwidths • Low transmission loss • Immunity to cross talk • Electrical Isolation • Small size and weight 2. Define refractive index • Ratio of the speed of light in free space to its speed in a given material. 3. What are the commonly used wavelengths in fiber optic systems? • Dense Wavelength division Multiplexing. 4. What are the typical core/cladding sizes (in microns) for multimode fiber? • The two types of fiber are multimode and single mode. Within these categories, fibers are identified by their core and cladding diameters expressed in microns (one millionth of a meter), e.g. 50/125 micron multimode fiber. • Most fibers are 125 microns in outside diameter - a micron is one one-millionth of a meter and 125 microns is 0.005 inches- a bit larger than the typical human hair. 5. Define mode field diameter. • The Diameter base protocol is intended to provide an Authentication, Authorization and Accounting (AAA) framework for applications such as network access or IP mobility. 6. What are the four factors that contribute to attenuation? • Scattering • Absorption • Macrobending • Microbending 7. What are the three types of dispersion? • Modal dispersion • Chromatic dispersion • Polarization mode dispersion 8. What is a dispersion compensating fiber? • A fiber that acts like an equalizer, negative dispersion canceling positive dispersion. 9. What is a narrower spectra advantageous in optical systems? • The light output...
Words: 877 - Pages: 4
...Kara Kliesen Professor Wendel English 122 30 June 2015 Benefits of the Mediterranean Diet The Mediterranean diet is based on the eating habits of people who live near the Mediterranean Sea. The diet is constructed around a very high intake of fruits, vegetables, whole grains, nuts and legumes; a moderate consumption of fish, shellfish, poultry, eggs, dairy and olive oil; and a very limited consumption of red meat, processed foods, sugary foods and saturated fats. Adequate consumption of water is necessary and wine can be consumed in moderation (Del Chierico, Vernocchi, Dallapiccola, Putignani). In recent years there has been significant scientific evidence suggesting that closely following the Mediterranean diet provides adequate nutrient intake and can help decrease the risk of non-communicable, chronic disease for which multiple factors including diet and lifestyle can be attributed (Egger). In order to decrease the risk for cardiovascular disease, type II diabetes, some cancers, increase overall well-being, and reduce the monetary burden of these chronic diseases, Americans should consider adopting the Mediterranean diet. Cardiovascular disease is the leading cause of death in the United States, with an estimated 610,000 people dying because of it each year. Poor diet and obesity are two of the leading risk factors associated with this disease (“Heart Disease Facts”). Because cardiovascular disease is considered a low-grade inflammatory disease, there has been great...
Words: 1734 - Pages: 7
