DOCSLIB.ORG

The Generation of ULF/ELF/VLF Waves in the Ionosphere by Modulated Heating

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

universe Review The Generation of ULF/ELF/VLF Waves in the Ionosphere by Modulated Heating Zhe Guo 1,2 , Hanxian Fang 1,* and Farideh Honary 2 1 College of Meteorology and Oceanography, National University of Defense Technology, Changsha 410073, China; [email protected] 2 Department of Physics, Lancaster University, Lancaster LA1 4YB, UK; [email protected] * Correspondence: [email protected] Abstract: One of the most important effects of ionospheric modification by high power, high fre- quency (HF) waves is the generation of ultra low frequency/extremely low frequency/very low frequency (ULF/ELF/VLF) waves by modulated heating. This paper reviews the scientific achieve- ments of the past five decades regarding the main mechanisms of excitation of ULF/ELF/VLF waves and discusses their characteristics, such as their electrojet dependency, the location of the source region, continuous and discontinuous waves, the number of HF arrays, and the suitable range of the modulation frequency for different proposed mechanisms. Finally, the outlook for future research in this area is presented. Keywords: powerful HF waves; ULF/ELF/VLF waves; modulated heating; ionospheric heating 1. Introduction Ultra low frequency (ULF, below 3 Hz)/extremely low frequency (ELF, 3-3000 Hz)/very low frequency (VLF, 3–30 kHz) [1] waves are important not only for the navigation, commu- Citation: Guo, Z.; Fang, H.; Honary, nication, and detection of underground targets, but also for the precipitation of energetic F. The Generation of ULF/ELF/VLF electrons in radiation belts, in order to protect astronauts and spacecrafts operating in Waves in the Ionosphere by these regions [2]. This is because, firstly, ULF/ELF/VLF waves can travel thousands Modulated Heating. Universe 2021, 7, of kilometers in the Earth-ionospheric waveguide. Secondly, ULF/ELF/VLF waves can 29. https://doi.org/10.3390/ propagate upwards, into the magnetosphere. The magnetosphere is a large, natural plasma universe7020029 laboratory that is filled with a large number of high-energy electrons. The energy of these Received: 17 December 2020 high-energy electrons ranges from about ~100 keV to several MeV, and electrons with a Accepted: 26 January 2021 higher energy (>2 MeV) are called “relativistic electrons” or “killer electrons”, which can Published: 29 January 2021 damage or even “kill” satellites. These “killer electrons” can be precipitated through the process of wave-particle interactions with ULF/ELF/VLF waves. This effect is of great Publisher’s Note: MDPI stays neutral practical significance with regards to eliminating the natural radiation belts or artificial with regard to jurisdictional claims in radiation belts caused by high-altitude nuclear explosions [3–5]. However, there are some published maps and institutional affil- disadvantages of directly transmitting ULF/ELF/VLF waves by ground-based antenna iations. arrays, such as the very large floor space, poor flexibility, low radiation efficiency, and high costs of use and maintenance, so there are difficulties in building such antenna arrays [6,7]. For example, the US Navy’s VLF antenna (as shown in Figure1) consists of 26 towers and the height of each is 850 to 1000 ft. Moreover, the power of 18 MW consumed by the Copyright: © 2021 by the authors. antenna is obtained from a dedicated power plant [8]. Furthermore, in the 1960s, the US Licensee MDPI, Basel, Switzerland. Navy devised a plan to build an ELF antenna called Project Sanguine, which would have This article is an open access article taken up 41 percent of the area of Wisconsin, but this project never came to fruition, mainly distributed under the terms and due to its overwhelming cost and the potential environmental impact [9]. Based on the conditions of the Creative Commons above reasons, alternate methods are in demand. Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). Universe 2021, 7, 29. https://doi.org/10.3390/universe7020029 https://www.mdpi.com/journal/universe Universe 2021, 7, 29 2 of 18 Universe 2020, 6, x FOR PEER REVIEW 2 of 17 FigureFigure 1. Very 1. Very low frequencylow frequency (VLF) antenna (VLF) ofantenna the US Navy. of the US Navy. IonosphericIonospheric heating heating by high by power, high high power, frequency high (HF,frequency 3–30 MHz) (HF, [10 3-30] radio MHz) waves [10] radio waves is a method of artificially modifying the ionosphere by transmitting high frequency radio is a method of artificially modifying the ionosphere by transmitting high frequency radio waves that can interact with ionospheric plasma and excite a series of non-linear physical processes.waves that The studycan interact of ionospheric with heatingionospheric by high plasma power high and frequency excite a radioseries waves of non-linear is physical anprocesses. interdisciplinary The study field of of radio ionospheric wave propagation, heating space by high science, power and plasma high frequency physics. It radio waves is hasan always interdisciplinary been an important field research of radio direction wave ofpropagation, space physics andspace radio science, physics. and The plasma physics. theoreticalIt has always study of been ionospheric an important heating includes research two direction kinds of non-linear of space effects: physics (1) Theand radio physics. thermal effect dominated by Ohmic heating and (2) parametric instability and electron accelerationThe theoretical due to the study electric of waveionospheric field. heating includes two kinds of non-linear effects: 1) TheIonospheric thermal effect modulated dominated heating by by high Ohmic power heating HF waves and is carried 2) parametric out by transmitting instability and electron HFacceleration waves modulated due byto ULF/ELF/VLFthe electric wave waves field. into the ionosphere, so that the ionosphere radiatesIonospheric expected ULF/ELF/VLF modulated waves heating under by ahigh series powe of non-linearr HF waves effects. is carried With the out by transmit- continuous improvement of theoretical and experimental research, modulated heating has becometing HF one waves of the mostmodulated significant by applications ULF/ELF/VLF of ionospheric waves into heating, the consistingionosphere, of a so that the iono- seriessphere of modulation radiates methodsexpected based ULF/ELF/VLF on different mechanisms. waves un Streltsovder a series et al. [ 11of] reviewednon-linear effects. With thethe various continuous modulation improvement methods and of providedtheoretical an excellentand experimental summary of research, experimental modulated heating andhas theoretical become investigationsone of the most regarding significant the different applicat ULF/ELF/VLFions of ionospheric wave generation heating, consisting of mechanisms.a series of Thismodulation review paper methods is focused based on theon characteristicsdifferent mechanisms. of each modulation Streltsov et al. [11] re- method and discusses topics that have not been covered in previous reviews, such as theviewed controversy the various of Beat Wavemodulation Modulation methods and the and new provided theory of Thermal an excellent Cubic Non-summary of experi- Linearity.mental Inand particular, theoretical the characteristics investigations of various regarding modulation the different methods are ULF/ELF/VLF summarized wave genera- andtion compared mechanisms. and two This possible review methods paper for is resolving focused theon controversythe characteristics of Beat Wave of each modulation Modulationmethod and are proposed.discusses topics that have not been covered in previous reviews, such as the The idea of generating ULF/ELF/VLF waves by ionospheric modulated heating was firstcontroversy proposed by of Willis Beat and Wave Davis Modulation [12], and was soon and tested the new successfully theory for of the Thermal first time Cubic by Non-Linear- Getmantsevity. In particular, et al. [13]. Itsthe basic characteristics principle is that of the va highrious frequency, modulation high power methods transmitter are summarized and “heater”compared is switched and two on and possible off with methods the frequency for resolving of the desired the ULF/ELF/VLFcontroversy of waves, Beat Wave Modula- givingtion riseare toproposed. increases and decreases of the local electron temperature with the modulation frequency.The Such idea periodic of generating changes in ULF/ELF/VLF the electron temperature waves cause by ionospheric corresponding modulated changes heating was in the electron density and conductivity, generating the modulation current. In the presence offirst an electrojet proposed in the by ionosphere, Willis and the Davis modulated [12], current and wa enhancess soon the tested current successfully and radiates for the first time theby low Getmantsev frequency signalet al. [13]. (as shown Its basic in Figure principle2[ 14]). is Thisthat methodthe high is frequency, called Amplitude high power transmit- ter “heater” is switched on and off with the frequency of the desired ULF/ELF/VLF waves, giving rise to increases and decreases of the local electron temperature with the modulation frequency. Such periodic changes in the electron temperature cause corresponding changes in the electron density and conductivity, generating the modulation current. In the presence of an electrojet in the ionosphere, the modulated current enhances the current and radiates the low frequency signal (as shown in Figure 2 [14]). This method is called Amplitude Mod- ulation (AM). Several other modulation methods that have the same
Recommended publications
  • WWVB: a Half Century of Delivering Accurate Frequency and Time by Radio

    WWVB: a Half Century of Delivering Accurate Frequency and Time by Radio

    Volume 119 (2014) http://dx.doi.org/10.6028/jres.119.004 Journal of Research of the National Institute of Standards and Technology WWVB: A Half Century of Delivering Accurate Frequency and Time by Radio Michael A. Lombardi and Glenn K. Nelson National Institute of Standards and Technology, Boulder, CO 80305 [email protected] [email protected] In commemoration of its 50th anniversary of broadcasting from Fort Collins, Colorado, this paper provides a history of the National Institute of Standards and Technology (NIST) radio station WWVB. The narrative describes the evolution of the station, from its origins as a source of standard frequency, to its current role as the source of time-of-day synchronization for many millions of radio controlled clocks. Key words: broadcasting; frequency; radio; standards; time. Accepted: February 26, 2014 Published: March 12, 2014 http://dx.doi.org/10.6028/jres.119.004 1. Introduction NIST radio station WWVB, which today serves as the synchronization source for tens of millions of radio controlled clocks, began operation from its present location near Fort Collins, Colorado at 0 hours, 0 minutes Universal Time on July 5, 1963. Thus, the year 2013 marked the station’s 50th anniversary, a half century of delivering frequency and time signals referenced to the national standard to the United States public. One of the best known and most widely used measurement services provided by the U. S. government, WWVB has spanned and survived numerous technological eras. Based on technology that was already mature and well established when the station began broadcasting in 1963, WWVB later benefitted from the miniaturization of electronics and the advent of the microprocessor, which made low cost radio controlled clocks possible that would work indoors.
  • EHC 238 Front Pages Final.Fm

    EHC 238 Front Pages Final.Fm

    This report contains the collective views of an international group of experts and does not necessarily represent the decisions or the stated policy of the International Commission of Non- Ionizing Radiation Protection, the International Labour Organization, or the World Health Organization. Environmental Health Criteria 238 EXTREMELY LOW FREQUENCY FIELDS Published under the joint sponsorship of the International Labour Organization, the International Commission on Non-Ionizing Radiation Protection, and the World Health Organization. WHO Library Cataloguing-in-Publication Data Extremely low frequency fields. (Environmental health criteria ; 238) 1.Electromagnetic fields. 2.Radiation effects. 3.Risk assessment. 4.Envi- ronmental exposure. I.World Health Organization. II.Inter-Organization Programme for the Sound Management of Chemicals. III.Series. ISBN 978 92 4 157238 5 (NLM classification: QT 34) ISSN 0250-863X © World Health Organization 2007 All rights reserved. Publications of the World Health Organization can be obtained from WHO Press, World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland (tel.: +41 22 791 3264; fax: +41 22 791 4857; e- mail: [email protected]). Requests for permission to reproduce or translate WHO publications – whether for sale or for noncommercial distribution – should be addressed to WHO Press, at the above address (fax: +41 22 791 4806; e-mail: [email protected]). The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.
  • Applied Engineering Using Schumann Resonance for Earthquakes Monitoring

    Applied Engineering Using Schumann Resonance for Earthquakes Monitoring

    applied sciences Article Applied Engineering Using Schumann Resonance for Earthquakes Monitoring Jose A. Gazquez 1,2, Rosa M. Garcia 1,2, Nuria N. Castellano 1,2 ID , Manuel Fernandez-Ros 1,2 ID , Alberto-Jesus Perea-Moreno 3 ID and Francisco Manzano-Agugliaro 1,* ID 1 Department Engineering, University of Almeria, CEIA3, 04120 Almeria, Spain; [email protected] (J.A.G.); [email protected] (R.M.G.); [email protected] (N.N.C.); [email protected] (M.F.-R.) 2 Research Group of Electronic Communications and Telemedicine TIC-019, 04120 Almeria, Spain 3 Department of Applied Physics, University of Cordoba, CEIA3, Campus de Rabanales, 14071 Córdoba, Spain; [email protected] * Correspondence: [email protected]; Tel.: +34-950-015396; Fax: +34-950-015491 Received: 14 September 2017; Accepted: 25 October 2017; Published: 27 October 2017 Abstract: For populations that may be affected, the risks of earthquakes and tsunamis are a major concern worldwide. Therefore, early detection of an event of this type in good time is of the highest priority. The observatories that are capable of detecting Extremely Low Frequency (ELF) waves (<300 Hz) today represent a breakthrough in the early detection and study of such phenomena. In this work, all earthquakes with tsunami associated in history and all existing ELF wave observatories currently located worldwide are represented. It was also noticed how the southern hemisphere lacks coverage in this matter. In this work, the most suitable locations are proposed to cover these geographical areas. Also, ELF data processed obtained from the observatory of the University of Almeria in Calar Alto, Spain are shown.
  • Through-The-Earth Electromagnetic Trapped Miner Location Systems. a Review

    Through-The-Earth Electromagnetic Trapped Miner Location Systems. a Review

    Open File Report: 127-85 THROUGH-THE-EARTH ELECTROMAGNETIC TRAPPED MINER LOCATION SYSTEMS. A REVIEW By Walter E. Pittman, Jr., Ronald H. Church, and J. T. McLendon Tuscaloosa Research Center, Tuscaloosa, Ala. UNITED STATES DEPARTMENT OF THE INTERIOR BUREAU OF MINES Research at the Tuscaloosa Research Center is carried out under a memorandum of agreement between the Bureau of Mines, U. S. Department of the Interior, and the University of Alabama. CONTENTS .Page List of abbreviations ............................................. 3 Abstract .......................................................... 4 Introduction ...................................................... 4 Early efforts at through-the-earth communications ................. 5 Background studies of earth electrical phenomena .................. 8 ~ationalAcademy of Engineering recommendations ................... 10 Theoretical studies of through-the-earth transmissions ............ 11 Electromagnetic noise studies .................................... 13 Westinghouse - Bureau of Mines system ............................ 16 First phase development and testing ............................. 16 Second phase development and testing ............................ 17 Frequency-shift keying (FSK) beacon signaler .................... 19 Anomalous effects ................................................ 20 Field testing and hardware evolution .............................. 22 Research in communication techniques .............................. 24 In-mine communication systems ....................................
  • What Is Rf? It's Like Magic

    What Is Rf? It's Like Magic

    Originally appeared in the December 2011 issue of Communications Technology. WHAT IS RF? IT’S LIKE MAGIC By RON HRANAC The cable industry has, since the very first systems in the late 1940s, embraced and been based on radio frequency (RF) technology. These days, we’ve also embraced the digital world — and a subset of digital technology called Internet protocol (IP) — but RF still is needed in most cable networks to transport digital data to and from devices in our subscribers’ homes. The answer to the question in the title of this month’s column is far more complicated than it seems initially. A good place to start is with an explanation of “R” and “F.” What’s radio frequency? Here’s one high-level perspective: It’s that portion of the electromagnetic spectrum from a few kilohertz to about 300 gigahertz. The radio-frequency part of the electromagnetic spectrum is further broken down into two chunks: radio waves and microwaves. Some references define radio waves as those with a frequency starting at about 3 kHz (the beginning of the very low frequency [VLF] band) and extending to 300 MHz (the beginning of the ultra high frequency [UHF] band), with microwaves covering roughly 300 MHz to 300 GHz. The latter is the beginning of the far infrared (FIR) portion of the electromagnetic spectrum. Other references have microwaves starting at frequencies higher than 300 MHz; indeed, many RF engineers consider the microwave spectrum to be higher than about 1 GHz. Radio frequency also can be defined as a rate of oscillation within the 3 kHz to 300 GHz range (more on this in a moment).
  • The Effect of the Ionosphere on Ultra-Low-Frequency Radio-Interferometric Observations? F

    The Effect of the Ionosphere on Ultra-Low-Frequency Radio-Interferometric Observations? F

    A&A 615, A179 (2018) Astronomy https://doi.org/10.1051/0004-6361/201833012 & © ESO 2018 Astrophysics The effect of the ionosphere on ultra-low-frequency radio-interferometric observations? F. de Gasperin1,2, M. Mevius3, D. A. Rafferty2, H. T. Intema1, and R. A. Fallows3 1 Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands e-mail: [email protected] 2 Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany 3 ASTRON – the Netherlands Institute for Radio Astronomy, PO Box 2, 7990 AA Dwingeloo, The Netherlands Received 13 March 2018 / Accepted 19 April 2018 ABSTRACT Context. The ionosphere is the main driver of a series of systematic effects that limit our ability to explore the low-frequency (<1 GHz) sky with radio interferometers. Its effects become increasingly important towards lower frequencies and are particularly hard to calibrate in the low signal-to-noise ratio (S/N) regime in which low-frequency telescopes operate. Aims. In this paper we characterise and quantify the effect of ionospheric-induced systematic errors on astronomical interferometric radio observations at ultra-low frequencies (<100 MHz). We also provide guidelines for observations and data reduction at these frequencies with the LOw Frequency ARray (LOFAR) and future instruments such as the Square Kilometre Array (SKA). Methods. We derive the expected systematic error induced by the ionosphere. We compare our predictions with data from the Low Band Antenna (LBA) system of LOFAR. Results. We show that we can isolate the ionospheric effect in LOFAR LBA data and that our results are compatible with satellite measurements, providing an independent way to measure the ionospheric total electron content (TEC).
  • Very-Low-Frequency Radio Propagation in the Ionosphere

    Very-Low-Frequency Radio Propagation in the Ionosphere

    JOURNAL OF RESEARCH of the National Bureau of Standards-D. Radio Propagation Vol. 66D, No. 6, November- December 1962 Very-Low-Frequency Radio Propagation In the Ionosphere Daniel W. Swift Contribution from Research and Advanced Development Division, Avco Corporation, Wilmington, Mass. (R eceived April 27, 1962 ; revised June 5, 1962) Equations describing the propagation of radio waves in a horizontally stratified a niso­ tropic ionosphere were developed by considering the limit.ing case of a la rge number of in­ finitesimall y t hin slabs of constant electron density a nd collision frequency. The quasi­ longitudin al approximation was used. The propagation equations appeared as four co upled first-order linear differential equations, co upled by gradients in electron density and collision frequency. The quasi-longit udina l a pproxima tion permitted use of particul a rl y s imple forms for t he co upling coe ffi cients, t hese forms bein g a menable to simple analysis. Coupling between two ordinary or two extraordinary modes was found to be co nsid erably stronger than cross coupling between ordinary a nd extraordinary mode . Cross couplin g was related to the rate of change of the direction of the phase normal. It was found that the re fl ection of VLF radio waves from t he daytime ionosphere is relatively insensitive to t he angle of incidence on the ionosphere except for highly oblique propagation. "Vhistler penetration was a lso found to be insensitive to the angle of in cid ence on the ionosphere. 1. Introduction In this report, we shall consider the full-'wave solutions for a very low frequency radio wave propagating obliquely into a horizontally stratified ionosphere.
  • Heart Rate Variability Analysis System

    Heart Rate Variability Analysis System

    Heart Rate Variability Analysis System Clinical Information VERSION 3.O. SA - 3000P Clinical Manual Clinical 3000P CONTENTS 1. ABOUT SA-3000P------------------------------------------------------------------------------------4 VER.3.0. 2. HRV, ITS BACKGROUND INFORMATION 2.1. HRV, ITS DEFINITION----------------------------------------------------------------------------------6 2.2. GENERATION OF HRV--------------------------------------------------------------------------------7 2.3. HISTORY OF HRV---------------------------------------------------------------------------------------9 2.4. ABOUT THE TASK FORCE--------------------------------------------------------------------------10 2.5. STRESS AND AUTOMNOMIC NERVOUS SYSTEM------------------------------------------11 2.6. THE MEANING OF DEPRESSED HRV-----------------------------------------------------------12 3. METHODOLOGY AND TERMINOLOGY OF HRV ANALYSIS 3.1. METHODOGOLY----------------------------------------------------------------------------------------14 3.2. TERMINOLOGY-----------------------------------------------------------------------------------------16 3.2.1. Time Domain parameters---------------------------------------------------------------------------16 3.2.1.1 SDNN 2 3.2.1.2 SDNN Index 3.2.1.3. RMS-SD 3.2.2. Frequency Domain Parameters----------------------------------------------------------------17 3.2.2.1. Total Power (TP) 3.2.2.2. Very Low Frequency (VLF) 3.2.2.3. Low Frequency (LF) 3.2.2.4. High Frequency (HF) 3.2.2.5. LF/HF Ratio 3.2.2.6. Normalized Low Frequency
  • Time and Frequency Users' Manual

    Time and Frequency Users' Manual

    ,>'.)*• r>rJfl HKra mitt* >\ « i If I * I IT I . Ip I * .aference nbs Publi- cations / % ^m \ NBS TECHNICAL NOTE 695 U.S. DEPARTMENT OF COMMERCE/National Bureau of Standards Time and Frequency Users' Manual 100 .U5753 No. 695 1977 NATIONAL BUREAU OF STANDARDS 1 The National Bureau of Standards was established by an act of Congress March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation's science and technology and facilitate their effective application for public benefit To this end, the Bureau conducts research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, a technical (3) basis for equity in trade, and (4) technical services to pro- mote public safety. The Bureau consists of the Institute for Basic Standards, the Institute for Materials Research the Institute for Applied Technology, the Institute for Computer Sciences and Technology, the Office for Information Programs, and the Office of Experimental Technology Incentives Program. THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United States of a complete and consist- ent system of physical measurement; coordinates that system with measurement systems of other nations; and furnishes essen- tial services leading to accurate and uniform physical measurements throughout the Nation's scientific community, industry, and commerce. The Institute consists of the Office of Measurement Services, and the following center and divisions: Applied Mathematics
  • Extremely Low Frequency (Elf) Fields

    Extremely Low Frequency (Elf) Fields

    This report contains the collective views of an international group of experts and does not necessarily represent the decisions or the stated policy of either the World Health Organization, the United Nations Environment Programme, or the International Radiation Protection As- sociation. Environmental Health Criteria 35 EXTREMELY LOW FREQUENCY (ELF) FIELDS - Published under the joint sponsorship of the United Nations Environment Programme, the World Health Organization, and the International Radiation Protection Association S World Health Organization V Geneva, 1984 Is- ISBN 92 4 154095 8 - ©World Health Organization 1984 Publications of the World Health Organization enjoy copyright protec- tion in accordance with the provisions of Protocol 2 of the Universal Copy- right Convention. For rights of reproduction or translation of WHO publica- tions, in part or in toto, application should be made to the Office of Publica- tions, World Health Organization, Geneva, Switzedand. The World Health Organization welcomes such applications. The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or con- cerning the delimitation of its frontiers or boundaries. The mention of specific companies of of certain manufacturers' products does not imply that they are endorsed or recommended by the World Health Organization in preference to others of a similar nature that are not men- tioned. Errors and omissions excepted, the names of proprietary products are distingthshed by initial capital letters. PRINTED IN FINLAND 8416131 vAI.4MALA - 5500 -3- CONTENTS Page ENVIRONMENTAL HEALTH CRITERIA FOR EXTREMELY LOW FREQUENCY (ELF) FIELDS I.
  • Wwvb Time Code

    Wwvb Time Code

    Time & Freq Sp Publication A 2/13/02 5:24 PM Page 1 NIST Special Publication 432, 2002 Edition NIST Time and Frequency Services Michael A. Lombardi Time & Freq Sp Publication A 4/22/03 1:32 PM Page 3 NIST Special Publication 432 (Minor text revisions made in April 2003) NIST Time and Frequency Services Michael A. Lombardi Time and Frequency Division Physics Laboratory (Supersedes NIST Special Publication 432, dated June 1991) January 2002 U.S. DEPARTMENT OF COMMERCE Donald L. Evans, Secretary TECHNOLOGY ADMINISTRATION Phillip J. Bond, Under Secretary for Technology NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY Arden L. Bement, Jr., Director Time & Freq Sp Publication A 2/13/02 5:24 PM Page 4 Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the entities, materials, or equipment are necessarily the best available for the purpose. NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY SPECIAL PUBLICATION 432 (SUPERSEDES NIST SPECIAL PUBLICATION 432, DATED JUNE 1991) NATL. INST.STAND.TECHNOL. SPEC. PUBL. 432, 76 PAGES (JANUARY 2002) CODEN: NSPUE2 U.S. GOVERNMENT PRINTING OFFICE WASHINGTON: 2002 For sale by the Superintendent of Documents, U.S. Government Printing Office Website: bookstore.gpo.gov Phone: (202) 512-1800 Fax: (202) 512-2250 Mail: Stop SSOP,Washington, DC 20402-0001
  • An Agile Laser with Ultra-Low Frequency Noise and High Sweep Linearity

    An Agile Laser with Ultra-Low Frequency Noise and High Sweep Linearity

    An agile laser with ultra-low frequency noise and high sweep linearity Haifeng Jiang 1,* , Fabien Kéfélian 2, Pierre Lemonde1, André Clairon 1 and Giorgio Santarelli 1 1Laboratoire National de Métrologie et d’Essais–Système de Références Temps-Espace, Observatoire de Paris, UPMC and CNRS, 61 Avenue de l’Observatoire, 75014 Paris, France 2Laboratoire de Physique des Lasers, Université Paris 13 and CNRS, 99 Avenue Jean-Baptiste Clément, 93430 Villetaneuse, France *[email protected] Abstract: We report on a fiber-stabilized agile laser with ultra-low frequency noise. The frequency noise power spectral density is comparable to that of an ultra-stable cavity stabilized laser at Fourier frequencies higher than 30 Hz. When it is chirped at a constant rate of ~ 40 MHz/s, the max non-linearity frequency error is about 50 Hz peak-to-peak over more than 600 MHz tuning range. The Rayleigh backscattering is found to be a significant frequency noise source dependent on fiber length, chirping rate and the power imbalance of the interferometer arms. We analyze this effect both theoretically and experimentally and put forward techniques to reduce this noise contribution. OCIS codes: (140.0140) Lasers and laser optics; (140.3425) Laser stabilization; (140.3518) Lasers, frequency modulated; (140.3600) Lasers, tunable; (290.5870) Scattering, Rayleigh. References and links 1. M. Harris, G. N. Pearson, J. M. Vaughan, D. Letalick, and C. Karlsson, “The role of laser coherence length in continuous-wave coherent laser radar,” J. Mod. Opt., 45 , 1567-1581, (1998). 2. R. W. Fox, C. W. Gates, and L. W. Hollberg, in Cavity-Enhanced Spectroscopies, R.