Intensity Modulation. Wei-Chih Wang Department of Mechanical Engineering University of Washington. W. Wang
|
|
- Marylou O’Brien’
- 5 years ago
- Views:
Transcription
1 Intensity Modulation Wei-Chih Wang Department of Mechanical Engineering University of Washington
2 Why Intensity Modulation Simple optical setup Broadband or mono-chormatic light source Less sensitive but cheaper to make
3 Intensity (Amplitude) Sensors In this case, the signal to be measured (the measurand), intensity (amplitude) modulates the light carried by an optical fiber or waveguide. For this class of sensors a normalized modulation index (m) can be defined as where, I = change in optical power as a result of modulation by the measurand; I 0 = optical power reaching the detector when there is no modulation; and P = perturbation (measurand).
4 Intensity Sensors The sensor response expressed as a differential voltage per unit change in measurand is given by S = q I o R m Where q = detector responsivity (A/W); R = load resistance. m= normalized modulation index
5 Limits on Performance 1. Signal voltage ~ noise voltage The minimum measurable quantity in the shot noise limit is given by, i 2 d = 2eBI d white noise With light: i d 2 = 2eBI p where e = electronic charge and B=detection bandwidth.
6 Noise in photodetectors N λ I p hυ detector electronics Radiation noise (quantum noise) Internal detector noise System noise Output Signal I p
7 Four noise sources often encountered in connection with optical detectors. Johnson noise Shot noise 1/f noise Photon noise
8 Sources of internal detector noise Johnson (thermal) noise 1. All resistive materials 2. Depends only on temp. and bandwidth of measuring system
9 The Johnson noise contribution is provided by the shunt resistance of the device, series resistance and the load resistance. The Johnson noise (thermal noise) is given by:
10 Johnson noise is generated by thermal fluctuations in conducting materials. It is sometimes called thermal noise. It results from the random motion of electrons in a conductor. The electrons are in constant motion, colliding with each other and with the atoms of the material. Each motion of an electron between collisions represents a tiny current. The sum of all these currents taken over a long period of time is zero, but their random fluctuations over short intervals constitute Johnson noise. To reduce the magnitude of Johnson noise, one may cool the system, especially the load resistor. One should reduce the value of the load resistance, although this is done at the price of reducing the available signal. One should keep the bandwidth of the amplification small; one Hz is a commonly employed value.
11 Shot noise Seen in photodiodes under reverse bias (dark current noise) with no photon input, I = I sat ( eqv/kt 1) = -I d (dark current) light instead) i 2 d = 2eBI d white noise With light: i d 2 = 2eBI p (a function of where e = electronic charge and B=detection bandwidth.
12 The term shot noise is derived from fluctuations in the stream of electrons in a vacuum tube. These variations create noise because of the random fluctuations in the arrival of electrons at the anode. The shot noise name arises from the similarity to the noise of a hail of shots striking a target. In semiconductors, the major source of shot noise is random variations in the rate at which charge carriers are generated and recombine. This noise, called generation-recombination or gr noise, is the semiconductor manifestation of shot noise. Shot noise may be minimized by keeping any DC component to the current small, especially the dark current, and by keeping the bandwidth of the amplification system small.
13 1/f noise Larger noise powers at lower frequencies. No theory: not well understood. Seems to be related to contacts, surfaces, other potential barriers B = bandwidth f = frequency I f2 ~ I 2 B/f Usually much smaller than shot noise except at very low frequency
14 The term 1/f noise (pronounced one over f) is used to describe a number of types of noise that are present when the modulation frequency f is low. This type of noise is also called excess noise because it exceeds shot noise at frequencies below a few hundred Hertz. The mechanisms that produce 1/f noise are poorly understood. The noise power is inversely proportional to f, the modulation frequency. This dependence of the noise power on modulation frequency leads to the name for this type of noise. To reduce 1/f noise, an optical detector should be operated at a reasonably high frequency, often as high as 1000 Hz. This is a high enough value to reduce the contribution of 1/f noise to a small amount.
15 Noise spectrum 1/f Measured Squared noise Current Per BW shot Johnson frequency
16 As an example: If a photodiode has a dark leakage current of 2 na and a shunt resistance of 5E8 Ohms, and a responsivity of 0.5 A/W, and letting the bandwidth of the system be 1 Hz, As an example: If a photodiode has a dark leakage current of 2 na and a shunt resistance of 5E8 Ohms, and a responsivity of 0.5 A/W, and letting the bandwidth of the system be 1 Hz, Shot noise is the dominant component of the noise current of a reverse-biased photodiode. This is particularly true at higher voltages (at break down i.e.). If devices are operated in a photovoltaic mode with zero bias, the Johnson noise dominates, as dark current approaches zero. When operating in the zero bias mode the noise current is reduced such that the NEP, and hence the minimum detectable signal, is reduced in spite of some loss of absolute sensitivity.
17 Macrobend (intrinsic) A large-scale bend that is visible; for example, a fiber wrapped around a person's finger. To prevent macrobends, all optical fiber (and optical fiber cable) has a minimum bend radius specification that should not be exceeded.
18 Macrobend (intrinsic) Macro-bend losses are losses observed when a fiber is bent to a radius of several centimeters. Large bending loss occurs at a critical bending radius of R c = 3n 12 λ 4π ( n n ) 3/ 2 2 where n 1 and n 2 are the indexes of refraction of core and cladding and λ is the operating wavelength. The optimum conditions for a large bending radius occur when refractive index difference between core and cladding is small or operating at a long wavelength.
19 Macrobend. Under the condition which a /R is to remain small, the light intensity attenuation is equal to γ B a + 2 = 10(log R) 2a where r is the core radius, and a specifies the shape of index of refraction (for a parabolic profile, a = 2 and for a step profile a =,) R is radius of curvature of the bend, is the relative refractive index difference between core and cladding. Based on the above equation, it is apparent that the bend loss can be enhanced with a smaller refractive index difference between core and cladding or by using a larger core radius of the guide. r R
20 Waveguide Sensor Array Higher spatial resolution (250µm x 250µm)
21 Basic Pressure Sensor Design pressure dimmer dimmer bend loss
22 Basic Shear Sensor Design shear displacement applied compression force sensor layers applied shear force original position sheared position sensor mesh high compliance
23 Microbend loss sensor (intrinsic) In an optical waveguide, a sharp curvatures involving local axial displacements of a few micrometers and spatial wavelengths of a few millimeters. microbending can cause significant radiative loss and mode coupling.
24 Microbend Sensor (intrinsic) Multimode fiber * fiber experiences multiple bends * lower order guided modes are converted to higher order modes and are eventually lost by radiation
25 Microbend Theory For pressure sensor, the transmission coefficient for light propagating through the bend fiber changed by the amount of applied pressure is equal to [1] T = T x A p Es As 1 T 1 ( k f + ) P Apk f P (1) l x s Where A p is area under the load, k f is the bent fiber force constant and A s, E s, l s are cross sectional area, Young s modulus and length of the mechanical deformer. The approximation is assume the deformer s A s E s /l s is much smaller than the fiber s k f.
26 For the optical portion of the modulation index T/ x, the loss occurs when wave number of the spatial distortion is equal to the difference in wave number between the modes. The period microbending induced along the fiber axis couples power between modes with longitudinal propagation constant is [1] 2π β m β n = (2) Λ where each mode has propagation constant β m = n 1 k cos( θ m ), with θ m representing the angle which the mode s equivalent rat makes with the fiber axis, n 1 core refractive index, and k is free space propagation constant, Λ is the mechanical distortion wavelength. Based on WKB approximation, the distance in β space between adjacent guide modes in a fiber is given by [2] δβ = 1 / 2 α 2 m + 1 β m = α 2 α + 2 β m (3) α + 2 r M where m is the order of modal group and M is total number of modes, α is a constant ( α = 2 for parabolic index fiber, α = for step index fiber), r is the core radius and is the fractional difference in refractive index between core and cladding [2]: = n n n n 1 n 1 n 2 for 1 where n 1 and n 2 are refractive indices for core and cladding.
27 In the case of parabolic index fiber, the equation (3) becomes, 2 δβ = (4) r It shows that δβ is independent of order of mode since all modes are equally spacing in k space (to within WKB approximation). This means that an efficient coupling between modes can be achieved with just one single spatial period. Since numerical aperture is defined as NA = n o sin θ o = ( n n (5) n 2 ) 1 ( 2 ) the spatial period based on the above NA and is [2] 2 2 π rn 1 Λ = π r = (6) NA In the case of step index, modes are not equally spaced and 2 m δβ = (7) r M The separation of modes in k space for step index is therefore depends on the order of the mode, m. Based on equation (2) and (7), we see larger the m, the smaller Λ and while lower order mode require larger period. The spatial period for highest order core modes coupled to radiated modes (assume m = M) is given by π r 2 π rn 1 Λ = (8) NA
28 The mechanical parameter also affects the outcome of the sensitivity of the sensor. The applied force and the resulted displacement x are related by simple F = k f x. Considering the bent fiber or waveguide as a bar loaded at the center and clamped at its ends [4] k 4 3π Esd η = 3 Λ f (9) Where d is diameter of the fiber and η is the number of bent intervals.
29 SMS Fiber Optics Sensor Electrical Engineering and Computer Science Laboratory for Electro-Optics and Sensor Systems Smetanova 17, SI-2000 Maribor, SLOVENIA The structure is composed of single mode leads and graded multimode sensor fiber.
30 SMS Fiber Optics Sensor Advantages higher sensitivity than classical microbend structures use of shorter deformers single mode leads, which eliminate intermodal interference problems sensitivity of 120%/N by use of low-sensitivity standard multimode fiber high insensitivity to macrobends
31 SMS Fiber Optics Sensor Faculty of Electrical Engineering and Computer Science Laboratory for Electro-Optics and Sensor Systems Smetanova 17, SI-2000 Maribor, SLOVENIA
32 SMS Fiber Optics Sensor Faculty of Electrical Engineering and Computer Science Laboratory for Electro-Optics and Sensor Systems Smetanova 17, SI-2000 Maribor, SLOVENIA
33 SMS Fiber Optics Sensor Faculty of Electrical Engineering and Computer Science Laboratory for Electro-Optics and Sensor Systems Smetanova 17, SI-2000 Maribor, SLOVENIA
34 SMS Fiber Optics Sensor Faculty of Electrical Engineering and Computer Science Laboratory for Electro-Optics and Sensor Systems Smetanova 17, SI-2000 Maribor, SLOVENIA
35 OTDR Optical Time Domain Reflectometer (OTDR) Intrinsic distributed sensors based on Rayleigh backscatter utilize either the measurand-dependent loss coefficient α(z) or backscattering coefficient r(z) mechanism in a single length of optical fiber which forms an extended sensor. The backscattering method was invented by M. Barnoskim and M. Jensen in 1976
36 OTDR Position of the optical impulse in the fiber core at time t
37 Basic Mechanisms of OTDR
38 OTDR Coherent OTDR (CO-OTDR) - The week returned backscattered signal is mixed with a strong coherent local oscillator optical signal to provide coherent amplification Correlation OTDR (COR-OTDR) COR-OTDR based on pseudorandom signal COR-OTDR based on Golay code signal Low correlation OTDR (LC-OTDR) Photon-Counting OTDR (PC-OTDR) Optical Frequency-Domain Reflectometry (OFDR) OFDR with the frequency scanning (OFDR-FS) OFDR with the synthesized coherence function (OFDR-SCF) Polarization OTDR (PO-OTDR)
39 Proximity Sensor (extrinsic) Liquid Level Sensors Distance Detection tube-mountable liquid level detection immersion type liquid level detection Reflective type Transmissive type By KEYENCE CORPORATION OF AMERICA
40 Liquid level sensor (extrinsic) A liquid-level sensor based on changes in the critical angle due to liquid level moving up to contact the sides of the prism (using total internal reflection in air).
41 Displacement Sensor (extrinsic) A change in the transverse alignment between two fibers changes the coupling and hence the power falling on the detector.
42 Accelerometer or Pressure Sensor (extrinsic) By, UW
43 Intensity modulation sensor (extrinsic) Quadrant fiber detector incoming coherent light source C A D waveguide in motion B Y X Figure 10. Quad cell photodiode position detector By, UW
44 Detector Scheme X = ((I A +I B )- (I C +I D ))/((I A +I B )+ (I C +I D )) Y= ((I A +I C )- (I B +I D ))/((I A +I B )+ (I C +I D )) I A, I B, I C, I D are Intensity from fiber A, B, C and D.
UNIT-II : SIGNAL DEGRADATION IN OPTICAL FIBERS
UNIT-II : SIGNAL DEGRADATION IN OPTICAL FIBERS The Signal Transmitting through the fiber is degraded by two mechanisms. i) Attenuation ii) Dispersion Both are important to determine the transmission characteristics
More informationFiberoptic and Waveguide Sensors
Fiberoptic and Waveguide Sensors Wei-Chih Wang Department of Mecahnical Engineering University of Washington Optical sensors Advantages: -immune from electromagnetic field interference (EMI) - extreme
More informationAbsorption: in an OF, the loss of Optical power, resulting from conversion of that power into heat.
Absorption: in an OF, the loss of Optical power, resulting from conversion of that power into heat. Scattering: The changes in direction of light confined within an OF, occurring due to imperfection in
More informationFiber Optic Communications Communication Systems
INTRODUCTION TO FIBER-OPTIC COMMUNICATIONS A fiber-optic system is similar to the copper wire system in many respects. The difference is that fiber-optics use light pulses to transmit information down
More informationOptical Fiber Technology. Photonic Network By Dr. M H Zaidi
Optical Fiber Technology Numerical Aperture (NA) What is numerical aperture (NA)? Numerical aperture is the measure of the light gathering ability of optical fiber The higher the NA, the larger the core
More informationFiber Optic Communication Systems. Unit-05: Types of Fibers. https://sites.google.com/a/faculty.muet.edu.pk/abdullatif
Unit-05: Types of Fibers https://sites.google.com/a/faculty.muet.edu.pk/abdullatif Department of Telecommunication, MUET UET Jamshoro 1 Optical Fiber Department of Telecommunication, MUET UET Jamshoro
More informationOptical behavior. Reading assignment. Topic 10
Reading assignment Optical behavior Topic 10 Askeland and Phule, The Science and Engineering of Materials, 4 th Ed.,Ch. 0. Shackelford, Materials Science for Engineers, 6 th Ed., Ch. 16. Chung, Composite
More informationSection B Lecture 5 FIBER CHARACTERISTICS
Section B Lecture 5 FIBER CHARACTERISTICS Material absorption Losses Material absorption is a loss mechanism related to material composition and fabrication process for the fiber. This results in dissipation
More informationNON-AMPLIFIED HIGH SPEED PHOTODETECTOR USER S GUIDE
NON-AMPLIFIED HIGH SPEED PHOTODETECTOR USER S GUIDE Thank you for purchasing your Non-amplified High Speed Photodetector. This user s guide will help answer any questions you may have regarding the safe
More informationGuided Propagation Along the Optical Fiber. Xavier Fernando Ryerson Comm. Lab
Guided Propagation Along the Optical Fiber Xavier Fernando Ryerson Comm. Lab The Nature of Light Quantum Theory Light consists of small particles (photons) Wave Theory Light travels as a transverse electromagnetic
More informationChapter 18: Fiber Optic and Laser Technology
Chapter 18: Fiber Optic and Laser Technology Chapter 18 Objectives At the conclusion of this chapter, the reader will be able to: Describe the construction of fiber optic cable. Describe the propagation
More informationGuided Propagation Along the Optical Fiber. Xavier Fernando Ryerson University
Guided Propagation Along the Optical Fiber Xavier Fernando Ryerson University The Nature of Light Quantum Theory Light consists of small particles (photons) Wave Theory Light travels as a transverse electromagnetic
More informationGuided Propagation Along the Optical Fiber
Guided Propagation Along the Optical Fiber The Nature of Light Quantum Theory Light consists of small particles (photons) Wave Theory Light travels as a transverse electromagnetic wave Ray Theory Light
More informationHIGH SPEED FIBER PHOTODETECTOR USER S GUIDE
HIGH SPEED FIBER PHOTODETECTOR USER S GUIDE Thank you for purchasing your High Speed Fiber Photodetector. This user s guide will help answer any questions you may have regarding the safe use and optimal
More informationIndustrial Instrumentation Prof. A. Barua Department of Electrical Engineering Indian Institute of Technology, Kharagpur
Industrial Instrumentation Prof. A. Barua Department of Electrical Engineering Indian Institute of Technology, Kharagpur Lecture - 29 Optoelectronic Sensor-II (Refer Slide Time: 00:36) Welcome to lesson
More informationCOM 46: ADVANCED COMMUNICATIONS jfm 07 FIBER OPTICS
FIBER OPTICS Fiber optics is a unique transmission medium. It has some unique advantages over conventional communication media, such as copper wire, microwave or coaxial cables. The major advantage is
More information14.2 Photodiodes 411
14.2 Photodiodes 411 Maximum reverse voltage is specified for Ge and Si photodiodes and photoconductive cells. Exceeding this voltage can cause the breakdown and severe deterioration of the sensor s performance.
More informationUNIT Write notes on broadening of pulse in the fiber dispersion?
UNIT 3 1. Write notes on broadening of pulse in the fiber dispersion? Ans: The dispersion of the transmitted optical signal causes distortion for both digital and analog transmission along optical fibers.
More informationPhysics of Waveguide Photodetectors with Integrated Amplification
Physics of Waveguide Photodetectors with Integrated Amplification J. Piprek, D. Lasaosa, D. Pasquariello, and J. E. Bowers Electrical and Computer Engineering Department University of California, Santa
More informationPhotonics and Fiber Optics
1 UNIT V Photonics and Fiber Optics Part-A 1. What is laser? LASER is the acronym for Light Amplification by Stimulated Emission of Radiation. The absorption and emission of light by materials has been
More informationLectureo5 FIBRE OPTICS. Unit-03
Lectureo5 FIBRE OPTICS Unit-03 INTRODUCTION FUNDAMENTAL IDEAS ABOUT OPTICAL FIBRE Multimode Fibres Multimode Step Index Fibres Multimode Graded Index Fibres INTRODUCTION In communication systems, there
More informationDepartment of Electrical Engineering and Computer Science
MASSACHUSETTS INSTITUTE of TECHNOLOGY Department of Electrical Engineering and Computer Science 6.161/6637 Practice Quiz 2 Issued X:XXpm 4/XX/2004 Spring Term, 2004 Due X:XX+1:30pm 4/XX/2004 Please utilize
More informationNON-AMPLIFIED PHOTODETECTOR USER S GUIDE
NON-AMPLIFIED PHOTODETECTOR USER S GUIDE Thank you for purchasing your Non-amplified Photodetector. This user s guide will help answer any questions you may have regarding the safe use and optimal operation
More informationOptical Receivers Theory and Operation
Optical Receivers Theory and Operation Photo Detectors Optical receivers convert optical signal (light) to electrical signal (current/voltage) Hence referred O/E Converter Photodetector is the fundamental
More informationMultimode Optical Fiber
Multimode Optical Fiber 1 OBJECTIVE Determine the optical modes that exist for multimode step index fibers and investigate their performance on optical systems. 2 PRE-LAB The backbone of optical systems
More informationFiber Optic Sensing Applications Based on Optical Propagation Mode Time Delay Measurement
R ESEARCH ARTICLE ScienceAsia 7 (1) : 35-4 Fiber Optic Sensing Applications Based on Optical Propagation Mode Time Delay Measurement PP Yupapin a * and S Piengbangyang b a Lightwave Technology Research
More informationInP-based Waveguide Photodetector with Integrated Photon Multiplication
InP-based Waveguide Photodetector with Integrated Photon Multiplication D.Pasquariello,J.Piprek,D.Lasaosa,andJ.E.Bowers Electrical and Computer Engineering Department University of California, Santa Barbara,
More informationOPTOELECTRONIC and PHOTOVOLTAIC DEVICES
OPTOELECTRONIC and PHOTOVOLTAIC DEVICES Outline 1. Introduction to the (semiconductor) physics: energy bands, charge carriers, semiconductors, p-n junction, materials, etc. 2. Light emitting diodes Light
More informationLecture 9 External Modulators and Detectors
Optical Fibres and Telecommunications Lecture 9 External Modulators and Detectors Introduction Where are we? A look at some real laser diodes. External modulators Mach-Zender Electro-absorption modulators
More information1. Explain in detail with necessary circuit diagram and advantages of trans impedance amplifier. [M/J-16] 10MARKS Transimpedance Preamplifier:
1. Explain in detail with necessary circuit diagram and advantages of trans impedance amplifier. [M/J-16] 10MARKS Transimpedance Preamplifier: Figure 4.11 Equivalent Circuit of the Transimpedance Receiver
More informationFiber Optics IV - Testing
PDHonline Course E311 (3 PDH) Fiber Optics IV - Testing Instructor: Lee Layton, PE 2012 PDH Online PDH Center 5272 Meadow Estates Drive Fairfax, VA 22030-6658 Phone & Fax: 703-988-0088 www.pdhonline.org
More informationis a method of transmitting information from one place to another by sending light through an optical fiber. The light forms an electromagnetic
is a method of transmitting information from one place to another by sending light through an optical fiber. The light forms an electromagnetic carrier wave that is modulated to carry information. The
More informationLecture 10. Dielectric Waveguides and Optical Fibers
Lecture 10 Dielectric Waveguides and Optical Fibers Slab Waveguide, Modes, V-Number Modal, Material, and Waveguide Dispersions Step-Index Fiber, Multimode and Single Mode Fibers Numerical Aperture, Coupling
More informationFIBER OPTICS. Prof. R.K. Shevgaonkar. Department of Electrical Engineering. Indian Institute of Technology, Bombay. Lecture: 20
FIBER OPTICS Prof. R.K. Shevgaonkar Department of Electrical Engineering Indian Institute of Technology, Bombay Lecture: 20 Photo-Detectors and Detector Noise Fiber Optics, Prof. R.K. Shevgaonkar, Dept.
More informationLaboratory of Optoelectornics
Department of Semiconductor of Optoelectronics Devices Laboratory of Optoelectornics Instruction 3 Measurement of the influence of fibers optisc macrobending on their attenuation. 1. Goal In this exercise
More informationLecture 8 Fiber Optical Communication Lecture 8, Slide 1
Lecture 8 Bit error rate The Q value Receiver sensitivity Sensitivity degradation Extinction ratio RIN Timing jitter Chirp Forward error correction Fiber Optical Communication Lecture 8, Slide Bit error
More informationDetectors for Optical Communications
Optical Communications: Circuits, Systems and Devices Chapter 3: Optical Devices for Optical Communications lecturer: Dr. Ali Fotowat Ahmady Sep 2012 Sharif University of Technology 1 Photo All detectors
More informationLecture 6 Fiber Optical Communication Lecture 6, Slide 1
Lecture 6 Optical transmitters Photon processes in light matter interaction Lasers Lasing conditions The rate equations CW operation Modulation response Noise Light emitting diodes (LED) Power Modulation
More informationThe absorption of the light may be intrinsic or extrinsic
Attenuation Fiber Attenuation Types 1- Material Absorption losses 2- Intrinsic Absorption 3- Extrinsic Absorption 4- Scattering losses (Linear and nonlinear) 5- Bending Losses (Micro & Macro) Material
More informationLecture 18: Photodetectors
Lecture 18: Photodetectors Contents 1 Introduction 1 2 Photodetector principle 2 3 Photoconductor 4 4 Photodiodes 6 4.1 Heterojunction photodiode.................... 8 4.2 Metal-semiconductor photodiode................
More informationHomework Set 3.5 Sensitive optoelectronic detectors: seeing single photons
Homework Set 3.5 Sensitive optoelectronic detectors: seeing single photons Due by 12:00 noon (in class) on Tuesday, Nov. 7, 2006. This is another hybrid lab/homework; please see Section 3.4 for what you
More informationModule 10 : Receiver Noise and Bit Error Ratio
Module 10 : Receiver Noise and Bit Error Ratio Lecture : Receiver Noise and Bit Error Ratio Objectives In this lecture you will learn the following Receiver Noise and Bit Error Ratio Shot Noise Thermal
More informationSkoog Chapter 1 Introduction
Skoog Chapter 1 Introduction Basics of Instrumental Analysis Properties Employed in Instrumental Methods Numerical Criteria Figures of Merit Skip the following chapters Chapter 2 Electrical Components
More informationOptical Communications
Optical Communications Telecommunication Engineering School of Engineering University of Rome La Sapienza Rome, Italy 2005-2006 Lecture #4, May 9 2006 Receivers OVERVIEW Photodetector types: Photodiodes
More informationOFCS OPTICAL DETECTORS 11/9/2014 LECTURES 1
OFCS OPTICAL DETECTORS 11/9/2014 LECTURES 1 1-Defintion & Mechanisms of photodetection It is a device that converts the incident light into electrical current External photoelectric effect: Electrons are
More informationFDM- FREQUENCY DIVISION MULTIPLEXING
FDM- FREQUENCY DIVISION MULTIPLEXING Multiplexing to refer to the combination of information streams from multiple sources for transmission over a shared medium Demultiplexing to refer to the separation
More informationPhotodiode: LECTURE-5
LECTURE-5 Photodiode: Photodiode consists of an intrinsic semiconductor sandwiched between two heavily doped p-type and n-type semiconductors as shown in Fig. 3.2.2. Sufficient reverse voltage is applied
More informationTypes of losses in optical fiber cable are: Due to attenuation, the power of light wave decreases exponentially with distance.
UNIT-II TRANSMISSION CHARACTERISTICS OF OPTICAL FIBERS SIGNAL ATTENUATION: Signal attenuation in an optical fiber is defined as the decrease in light power during light propagation along an optical fiber.
More informationWaveguides and Optical Fibers
Waveguides and Optical Fibers Dielectric Waveguides Light Light Light n n Light n > n A planar dielectric waveguide has a central rectangular region of higher refractive index n than the surrounding region
More informationCoherent Receivers Principles Downconversion
Coherent Receivers Principles Downconversion Heterodyne receivers mix signals of different frequency; if two such signals are added together, they beat against each other. The resulting signal contains
More informationHow to Speak Fiber Geek Article 2 Critical Optical Parameters Attenuation
Article 2 Critical Optical Parameters Attenuation Welcome back, Fiber Geeks! Article 1 in this series highlighted some bandwidth demand drivers and introductory standards information. The article also
More informationAgilOptics mirrors increase coupling efficiency into a 4 µm diameter fiber by 750%.
Application Note AN004: Fiber Coupling Improvement Introduction AgilOptics mirrors increase coupling efficiency into a 4 µm diameter fiber by 750%. Industrial lasers used for cutting, welding, drilling,
More informationIntroduction to Analog And Digital Communications
Introduction to Analog And Digital Communications Second Edition Simon Haykin, Michael Moher Chapter 11 System and Noise Calculations 11.1 Electrical Noise 11.2 Noise Figure 11.3 Equivalent Noise Temperature
More informationFIBER OPTICS. Prof. R.K. Shevgaonkar. Department of Electrical Engineering. Indian Institute of Technology, Bombay. Lecture: 4
FIBER OPTICS Prof. R.K. Shevgaonkar Department of Electrical Engineering Indian Institute of Technology, Bombay Lecture: 4 Modal Propagation of Light in an Optical Fiber Fiber Optics, Prof. R.K. Shevgaonkar,
More informationOptics and Lasers. Matt Young. Including Fibers and Optical Waveguides
Matt Young Optics and Lasers Including Fibers and Optical Waveguides Fourth Revised Edition With 188 Figures Springer-Verlag Berlin Heidelberg New York London Paris Tokyo Hong Kong Barcelona Budapest Contents
More informationEC Optical Communication And Networking TWO MARKS QUESTION AND ANSWERS UNIT -1 INTRODUCTION
EC6702 - Optical Communication And Networking TWO MARKS QUESTION AND ANSWERS UNIT -1 INTRODUCTION Ray Theory Transmission 1. Write short notes on ray optics theory. Laws governing the nature of light are
More informationPhotonics and Optical Communication
Photonics and Optical Communication (Course Number 300352) Spring 2007 Dr. Dietmar Knipp Assistant Professor of Electrical Engineering http://www.faculty.iu-bremen.de/dknipp/ 1 Photonics and Optical Communication
More informationOptical Signal Processing
Optical Signal Processing ANTHONY VANDERLUGT North Carolina State University Raleigh, North Carolina A Wiley-Interscience Publication John Wiley & Sons, Inc. New York / Chichester / Brisbane / Toronto
More informationNotes on Optical Amplifiers
Notes on Optical Amplifiers Optical amplifiers typically use energy transitions such as those in atomic media or electron/hole recombination in semiconductors. In optical amplifiers that use semiconductor
More informationMicro-sensors - what happens when you make "classical" devices "small": MEMS devices and integrated bolometric IR detectors
Micro-sensors - what happens when you make "classical" devices "small": MEMS devices and integrated bolometric IR detectors Dean P. Neikirk 1 MURI bio-ir sensors kick-off 6/16/98 Where are the targets
More informationOptodevice Data Book ODE I. Rev.9 Mar Opnext Japan, Inc.
Optodevice Data Book ODE-408-001I Rev.9 Mar. 2003 Opnext Japan, Inc. Section 1 Operating Principles 1.1 Operating Principles of Laser Diodes (LDs) and Infrared Emitting Diodes (IREDs) 1.1.1 Emitting Principles
More informationMAHALAKSHMI ENGINEERING COLLEGE TIRUCHIRAPALLI
MAHALAKSHMI ENGINEERING COLLEGE TIRUCHIRAPALLI - 621213 DEPARTMENT : ECE SUBJECT NAME : OPTICAL COMMUNICATION & NETWORKS SUBJECT CODE : EC 2402 UNIT IV: FIBER OPTIC RECEIVER AND MEASUREMENT PART -A (2
More informationAntennas & Propagation. CSG 250 Fall 2007 Rajmohan Rajaraman
Antennas & Propagation CSG 250 Fall 2007 Rajmohan Rajaraman Introduction An antenna is an electrical conductor or system of conductors o Transmission - radiates electromagnetic energy into space o Reception
More informationComponents of Optical Instruments
Components of Optical Instruments General Design of Optical Instruments Sources of Radiation Wavelength Selectors (Filters, Monochromators, Interferometers) Sample Containers Radiation Transducers (Detectors)
More informationChap14. Photodiode Detectors
Chap14. Photodiode Detectors Mohammad Ali Mansouri-Birjandi mansouri@ece.usb.ac.ir mamansouri@yahoo.com Faculty of Electrical and Computer Engineering University of Sistan and Baluchestan (USB) Design
More informationNEW YORK CITY COLLEGE of TECHNOLOGY
NEW YORK CITY COLLEGE of TECHNOLOGY THE CITY UNIVERSITY OF NEW YORK DEPARTMENT OF ELECTRICAL AND TELECOMMUNICATIONS ENGINEERING TECHNOLOGY Course : Prepared by: TCET 4102 Fiber-optic communications Module
More informationUNIT - 5 OPTICAL RECEIVER
UNIT - 5 LECTURE-1 OPTICAL RECEIVER Introduction, Optical Receiver Operation, receiver sensitivity, quantum limit, eye diagrams, coherent detection, burst mode receiver operation, Analog receivers. RECOMMENDED
More informationOptical fibre. Principle and applications
Optical fibre Principle and applications Circa 2500 B.C. Earliest known glass Roman times-glass drawn into fibers Venice Decorative Flowers made of glass fibers 1609-Galileo uses optical telescope 1626-Snell
More informationBragg and fiber gratings. Mikko Saarinen
Bragg and fiber gratings Mikko Saarinen 27.10.2009 Bragg grating - Bragg gratings are periodic perturbations in the propagating medium, usually periodic variation of the refractive index - like diffraction
More information2. The Basic principle of optical fibre (Or) Working principle of optical fibre (or) Total internal reflection
Introduction Fibre optics deals with the light propagation through thin glass fibres. Fibre optics plays an important role in the field of communication to transmit voice, television and digital data signals
More informationDETECTORS Important characteristics: 1) Wavelength response 2) Quantum response how light is detected 3) Sensitivity 4) Frequency of response
DETECTORS Important characteristics: 1) Wavelength response 2) Quantum response how light is detected 3) Sensitivity 4) Frequency of response (response time) 5) Stability 6) Cost 7) convenience Photoelectric
More informationEE119 Introduction to Optical Engineering Spring 2003 Final Exam. Name:
EE119 Introduction to Optical Engineering Spring 2003 Final Exam Name: SID: CLOSED BOOK. THREE 8 1/2 X 11 SHEETS OF NOTES, AND SCIENTIFIC POCKET CALCULATOR PERMITTED. TIME ALLOTTED: 180 MINUTES Fundamental
More informationInP-based Waveguide Photodetector with Integrated Photon Multiplication
InP-based Waveguide Photodetector with Integrated Photon Multiplication D.Pasquariello,J.Piprek,D.Lasaosa,andJ.E.Bowers Electrical and Computer Engineering Department University of California, Santa Barbara,
More informationOutline. Noise and Distortion. Noise basics Component and system noise Distortion INF4420. Jørgen Andreas Michaelsen Spring / 45 2 / 45
INF440 Noise and Distortion Jørgen Andreas Michaelsen Spring 013 1 / 45 Outline Noise basics Component and system noise Distortion Spring 013 Noise and distortion / 45 Introduction We have already considered
More informationOptical Amplifiers. Continued. Photonic Network By Dr. M H Zaidi
Optical Amplifiers Continued EDFA Multi Stage Designs 1st Active Stage Co-pumped 2nd Active Stage Counter-pumped Input Signal Er 3+ Doped Fiber Er 3+ Doped Fiber Output Signal Optical Isolator Optical
More informationFigure Responsivity (A/W) Figure E E-09.
OSI Optoelectronics, is a leading manufacturer of fiber optic components for communication systems. The products offer range for Silicon, GaAs and InGaAs to full turnkey solutions. Photodiodes are semiconductor
More informationFIBER OPTICS. Prof. R.K. Shevgaonkar. Department of Electrical Engineering. Indian Institute of Technology, Bombay. Lecture: 18.
FIBER OPTICS Prof. R.K. Shevgaonkar Department of Electrical Engineering Indian Institute of Technology, Bombay Lecture: 18 Optical Sources- Introduction to LASER Diodes Fiber Optics, Prof. R.K. Shevgaonkar,
More informationTSEK02: Radio Electronics Lecture 6: Propagation and Noise. Ted Johansson, EKS, ISY
TSEK02: Radio Electronics Lecture 6: Propagation and Noise Ted Johansson, EKS, ISY 2 Propagation and Noise - Channel and antenna: not in the Razavi book - Noise: 2.3 The wireless channel The antenna Signal
More informationBasic concepts. Optical Sources (b) Optical Sources (a) Requirements for light sources (b) Requirements for light sources (a)
Optical Sources (a) Optical Sources (b) The main light sources used with fibre optic systems are: Light-emitting diodes (LEDs) Semiconductor lasers (diode lasers) Fibre laser and other compact solid-state
More informationYou won t be able to measure the incident power precisely. The readout of the power would be lower than the real incident power.
1. a) Given the transfer function of a detector (below), label and describe these terms: i. dynamic range ii. linear dynamic range iii. sensitivity iv. responsivity b) Imagine you are using an optical
More informationEC Transmission Lines And Waveguides
EC6503 - Transmission Lines And Waveguides UNIT I - TRANSMISSION LINE THEORY A line of cascaded T sections & Transmission lines - General Solution, Physical Significance of the Equations 1. Define Characteristic
More informationApplication Instruction 002. Superluminescent Light Emitting Diodes: Device Fundamentals and Reliability
I. Introduction II. III. IV. SLED Fundamentals SLED Temperature Performance SLED and Optical Feedback V. Operation Stability, Reliability and Life VI. Summary InPhenix, Inc., 25 N. Mines Road, Livermore,
More informationNon-amplified High Speed Photodetectors
Non-amplified High Speed Photodetectors User Guide (800)697-6782 sales@eotech.com www.eotech.com Page 1 of 6 EOT NON-AMPLIFIED HIGH SPEED PHOTODETECTOR USER S GUIDE Thank you for purchasing your Non-amplified
More informationAnalysis of Self Phase Modulation Fiber nonlinearity in Optical Transmission System with Dispersion
36 Analysis of Self Phase Modulation Fiber nonlinearity in Optical Transmission System with Dispersion Supreet Singh 1, Kulwinder Singh 2 1 Department of Electronics and Communication Engineering, Punjabi
More informationThe electric field for the wave sketched in Fig. 3-1 can be written as
ELECTROMAGNETIC WAVES Light consists of an electric field and a magnetic field that oscillate at very high rates, of the order of 10 14 Hz. These fields travel in wavelike fashion at very high speeds.
More informationDifferential interrogation of FBG sensors using conventional optical time domain reflectometry
Differential interrogation of FBG sensors using conventional optical time domain reflectometry Yuri N. Kulchin, Anatoly M. Shalagin, Oleg B. Vitrik, Sergey A. Babin, Anton V. Dyshlyuk, Alexander A. Vlasov
More informationExamination Optoelectronic Communication Technology. April 11, Name: Student ID number: OCT1 1: OCT 2: OCT 3: OCT 4: Total: Grade:
Examination Optoelectronic Communication Technology April, 26 Name: Student ID number: OCT : OCT 2: OCT 3: OCT 4: Total: Grade: Declaration of Consent I hereby agree to have my exam results published on
More informationMobile Radio Propagation: Small-Scale Fading and Multi-path
Mobile Radio Propagation: Small-Scale Fading and Multi-path 1 EE/TE 4365, UT Dallas 2 Small-scale Fading Small-scale fading, or simply fading describes the rapid fluctuation of the amplitude of a radio
More informationEXAMINATION FOR THE DEGREE OF B.E. and M.E. Semester
EXAMINATION FOR THE DEGREE OF B.E. and M.E. Semester 2 2009 101908 OPTICAL COMMUNICATION ENGINEERING (Elec Eng 4041) 105302 SPECIAL STUDIES IN MARINE ENGINEERING (Elec Eng 7072) Official Reading Time:
More informationWave & Electromagnetic Spectrum Notes
Wave & Electromagnetic Spectrum Notes December 17, 2011 I.) Properties of Waves A) Wave: A periodic disturbance in a solid, liquid or gas as energy is transmitted through a medium ( Waves carry energy
More informationOptical Fiber. n 2. n 1. θ 2. θ 1. Critical Angle According to Snell s Law
ECE 271 Week 10 Critical Angle According to Snell s Law n 1 sin θ 1 = n 1 sin θ 2 θ 1 and θ 2 are angle of incidences The angle of incidence is measured with respect to the normal at the refractive boundary
More informationLecture 4 INTEGRATED PHOTONICS
Lecture 4 INTEGRATED PHOTONICS What is photonics? Photonic applications use the photon in the same way that electronic applications use the electron. Devices that run on light have a number of advantages
More informationFibre Optic Sensors: basic principles and most common applications
SMR 1829-21 Winter College on Fibre Optics, Fibre Lasers and Sensors 12-23 February 2007 Fibre Optic Sensors: basic principles and most common applications (PART 2) Hypolito José Kalinowski Federal University
More informationEENG473 Mobile Communications Module 3 : Week # (12) Mobile Radio Propagation: Small-Scale Path Loss
EENG473 Mobile Communications Module 3 : Week # (12) Mobile Radio Propagation: Small-Scale Path Loss Introduction Small-scale fading is used to describe the rapid fluctuation of the amplitude of a radio
More informationFigure Figure E E-09. Dark Current (A) 1.
OSI Optoelectronics, is a leading manufacturer of fiber optic components for communication systems. The products offer range for Silicon, GaAs and InGaAs to full turnkey solutions. Photodiodes are semiconductor
More information2 in the multipath dispersion of the optical fibre. (b) Discuss the merits and drawbacks of cut bouls method of measurement of alternation.
B.TECH IV Year I Semester (R09) Regular Examinations, November 2012 1 (a) Derive an expression for multiple time difference tt 2 in the multipath dispersion of the optical fibre. (b) Discuss the merits
More informationFiber Optic Communication Link Design
Fiber Optic Communication Link Design By Michael J. Fujita, S.K. Ramesh, PhD, Russell L. Tatro Abstract The fundamental building blocks of an optical fiber transmission link are the optical source, the
More informationUNIT-III SOURCES AND DETECTORS. According to the shape of the band gap as a function of the momentum, semiconductors are classified as
UNIT-III SOURCES AND DETECTORS DIRECT AND INDIRECT BAND GAP SEMICONDUCTORS: According to the shape of the band gap as a function of the momentum, semiconductors are classified as 1. Direct band gap semiconductors
More informationPhotons and solid state detection
Photons and solid state detection Photons represent discrete packets ( quanta ) of optical energy Energy is hc/! (h: Planck s constant, c: speed of light,! : wavelength) For solid state detection, photons
More informationIntroduction to Fiber Optics
Introduction to Fiber Optics Dr. Anurag Srivastava Atal Bihari Vajpayee Indian Institute of Information Technology and Manegement, Gwalior Milestones in Electrical Communication 1838 Samuel F.B. Morse
More information