1、 TSB-172-A (Revision of TSB-172) February 2013High Data Rate Multimode Fiber Transmission Techniques NOTICE TIA Engineering Standards and Publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeability
2、 and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for their particular need. The existence of such Standards and Publications shall not in any respect preclude any member or non-member of TIA from manufacturing or selling produ
3、cts not conforming to such Standards and Publications. Neither shall the existence of such Standards and Publications preclude their voluntary use by Non-TIA members, either domestically or internationally. Standards and Publications are adopted by TIA in accordance with the American National Standa
4、rds Institute (ANSI) patent policy. By such action, TIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Standard or Publication. This Standard does not purport to address all safety problems associated with its use or all applicab
5、le regulatory requirements. It is the responsibility of the user of this Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations before its use. (From Project No. TIA-PN-172-A, formulated under the cognizance of the TIA TR-42 Telecom
6、munications Cabling Systems, TR-42.11 Subcommittee on Optical Systems (568). . Published by TELECOMMUNICATIONS INDUSTRY ASSOCIATION Standards and Technology Department 1320 N. Courthouse Road Arlington, VA 22201 U.S.A. PRICE: Please refer to current Catalog of TIA TELECOMMUNICATIONS INDUSTRY ASSOCIA
7、TION STANDARDS AND ENGINEERING PUBLICATIONS or call IHS, USA and Canada (1-877-413-5187) International (303-397-2896) or search online at http:/www.tiaonline.org/standards/catalog/ All rights reserved Printed in U.S.A. NOTICE OF COPYRIGHT This document is copyrighted by the TIA. Reproduction of thes
8、e documents either in hard copy or soft copy (including posting on the web) is prohibited without copyright permission. For copyright permission to reproduce portions of this document, please contact the TIA Standards Department or go to the TIA website (www.tiaonline.org) for details on how to requ
9、est permission. Details are located at: http:/www.tiaonline.org/standards/catalog/info.cfm#copyright or Telecommunications Industry Association Technology (b) there is no assurance that the Document will be approved by any Committee of TIA or any other body in its present or any other form; (c) the
10、Document may be amended, modified or changed in the standards development or any editing process. The use or practice of contents of this Document may involve the use of intellectual property rights (“IPR”), including pending or issued patents, or copyrights, owned by one or more parties. TIA makes
11、no search or investigation for IPR. When IPR consisting of patents and published pending patent applications are claimed and called to TIAs attention, a statement from the holder thereof is requested, all in accordance with the Manual. TIA takes no position with reference to, and disclaims any oblig
12、ation to investigate or inquire into, the scope or validity of any claims of IPR. TIA will neither be a party to discussions of any licensing terms or conditions, which are instead left to the parties involved, nor will TIA opine or judge whether proposed licensing terms or conditions are reasonable
13、 or non-discriminatory. TIA does not warrant or represent that procedures or practices suggested or provided in the Manual have been complied with as respects the Document or its contents. If the Document contains one or more Normative References to a document published by another organization (“oth
14、er SSO”) engaged in the formulation, development or publication of standards (whether designated as a standard, specification, recommendation or otherwise), whether such reference consists of mandatory, alternate or optional elements (as defined in the TIA Engineering Manual, 4thedition) then (i) TI
15、A disclaims any duty or obligation to search or investigate the records of any other SSO for IPR or letters of assurance relating to any such Normative Reference; (ii) TIAs policy of encouragement of voluntary disclosure (see Engineering Manual Section 6.5.1) of Essential Patent(s) and published pen
16、ding patent applications shall apply; and (iii) Information as to claims of IPR in the records or publications of the other SSO shall not constitute identification to TIA of a claim of Essential Patent(s) or published pending patent applications. TIA does not enforce or monitor compliance with the c
17、ontents of the Document. TIA does not certify, inspect, test or otherwise investigate products, designs or services or any claims of compliance with the contents of the Document. ALL WARRANTIES, EXPRESS OR IMPLIED, ARE DISCLAIMED, INCLUDING WITHOUT LIMITATION, ANY AND ALL WARRANTIES CONCERNING THE A
18、CCURACY OF THE CONTENTS, ITS FITNESS OR APPROPRIATENESS FOR A PARTICULAR PURPOSE OR USE, ITS MERCHANTABILITY AND ITS NONINFRINGEMENT OF ANY THIRD PARTYS INTELLECTUAL PROPERTY RIGHTS. TIA EXPRESSLY DISCLAIMS ANY AND ALL RESPONSIBILITIES FOR THE ACCURACY OF THE CONTENTS AND MAKES NO REPRESENTATIONS OR
19、 WARRANTIES REGARDING THE CONTENTS COMPLIANCE WITH ANY APPLICABLE STATUTE, RULE OR REGULATION, OR THE SAFETY OR HEALTH EFFECTS OF THE CONTENTS OR ANY PRODUCT OR SERVICE REFERRED TO IN THE DOCUMENT OR PRODUCED OR RENDERED TO COMPLY WITH THE CONTENTS. TIA SHALL NOT BE LIABLE FOR ANY AND ALL DAMAGES, D
20、IRECT OR INDIRECT, ARISING FROM OR RELATING TO ANY USE OF THE CONTENTS CONTAINED HEREIN, INCLUDING WITHOUT LIMITATION ANY AND ALL INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES (INCLUDING DAMAGES FOR LOSS OF BUSINESS, LOSS OF PROFITS, LITIGATION, OR THE LIKE), WHETHER BASED UPON BREACH OF CO
21、NTRACT, BREACH OF WARRANTY, TORT (INCLUDING NEGLIGENCE), PRODUCT LIABILITY OR OTHERWISE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. THE FOREGOING NEGATION OF DAMAGES IS A FUNDAMENTAL ELEMENT OF THE USE OF THE CONTENTS HEREOF, AND THESE CONTENTS WOULD NOT BE PUBLISHED BY TIA WITHOUT SUCH LIM
22、ITATIONS. TIA TSB-172-A i High Data Rate Multimode Fiber Transmission Techniques Table of Contents FOREWORD . 1 1 INTRODUCTION . 2 2 SCOPE 2 3 DEFINITION OF TERMS, ACRONYMS AND ABBREVIATIONS, UNITS OF MEASURE 2 3.1 Definition of Terms . 2 3.2 Acronyms and Abbreviations . 2 3.3 Units of Measure 3 4 S
23、OME TRANSMISSION TECHNIQUES AND TECHNOLOGIES . 4 4.1 General 4 4.2 Serial Transmission 7 4.3 Dispersion Management 8 4.4 Multiplexing 12 4.5 Line Coding 16 4.6 Forward Error Correction (FEC) . 18 5 SUMMARY 20 ANNEX A (INFORMATIVE) References . 22 ANNEX B (INFORMATIVE) Possible key specifications for
24、 wider wavelength spectrum laser-optimized 50/125-m fibers . 24 List of Figures Figure 1 Block diagram of digital transmission system 4 Figure 2 Channel power budget . 5 Figure 3 Attenuation and dispersion waveform impairments . 6 Figure 4 Serial transmission concept . 7 Figure 5 Example of pre-emph
25、asized waveform . 9 Figure 6 Feed-forward equalizer architecture 11 Figure 7 Decision feedback equalizer architecture 11 Figure 8 Space division multiplexing on parallel fibers 13 Figure 9 Wavelength multiplexing concept 14 Figure 10 Tuning range for fibers providing 2000 MHzkm over a 150-nm spectru
26、m . 15 Figure 11 Commonly used binary line coding formats . 17 TIA TSB-172-A Figure 12 Binary NRZ and ternary line coding formats 18 List of Tables Table 1: Summary of Transmission Techniques . 21 Table B-1: Possible key performance specifications for laser-optimized 50/125-m fiber with a wider wave
27、length spectrum than specified in ANSI/TIA-492AAAC . 24 TIA TSB-172-A 1 FOREWORD (This foreword is not part of this Telecommunications Systems Bulletin) TIA Telecommunications Systems Bulletins (TSBs) are developed within the Technical Engineering Committees of the TIA and the standards coordinating
28、 committees of the TIA standards board. Members of the committees serve voluntarily and without commission. The companies that they represent are not necessarily members of the TIA. The standards developed within the TIA represent a consensus of the broad expertise on the subject. This expertise com
29、es from within the TIA as well as those outside of the TIA that have an expressed interest. The viewpoint expressed at the time that this Telecommunication Systems Bulletin was approved was from the contributors experience and the state of the art at that time. Users are encouraged to verify that th
30、ey have the latest revision of the document. TIA TSB-172-A 2 1 INTRODUCTION For local area networks (LANs) and storage area networks (SANs) the most widely deployed transmission format on multimode fiber at rates up to 10 Gb/s has been simple binary baseband serial transmission. As rates climbed fro
31、m 10 to 100 to 1,000 to 10,000 Mb/s, the basic approach was to speed up all the components commensurately. For data transmission rates above 10 Gb/s, a combination of alternative techniques has started to be employed to produce optimal multimode solutions. This TSB provides general insight into thes
32、e techniques and their associated benefits. 2 SCOPE This TSB reviews some techniques and technologies that can be applied to address high-rate transmission for multimode fiber systems. These techniques include serial and multiplexed transmission, dispersion compensation, and forward error correction
33、 technologies. Multi-level coding is examined as an alternative to the commonly used binary code. Possible key specifications appear in Annex B for a laser-optimized 50/125-m multimode fiber that provides wider wavelength spectrum relative to the specifications in TIA-492AAAC. This is an example of
34、what can be achieved to enhance the performance of systems using wavelength division multiplexing. 3 DEFINITION OF TERMS, ACRONYMS AND ABBREVIATIONS, UNITS OF MEASURE 3.1 Definition of Terms For the purposes of this TSB, the following definitions apply. Bit Error Ratio: the ratio of bits received in
35、 error to all bits received. Channel: a transmission path consisting of a transmitter, medium and receiver. Symbol: the smallest unit of transmitted information, discernable from other symbols by its duration or a change in characteristic such as amplitude or phase. A rate of 1 symbol per second = 1
36、 baud. 3.2 Acronyms and Abbreviations 100GE 100 gigabit Ethernet 10GE 10 gigabit Ethernet 16GFC 16 gigabit Fibre Channel 32GFC 32 gigabit Fibre Channel 40GE 40 gigabit Ethernet 8B10B 8 bit 10 bit ANSI American National Standards Institute ADC analog-to-digital converter TIA TSB-172-A 3 APD avalanche
37、 photo diode BER bit error ratio CDCF chromatic dispersion compensating fiber CWDM coarse wavelength division multiplexing DCF dispersion compensating fiber DEMUX demultiplexer DFE decision-feedback equalizer DMD differential mode delay DWDM dense wavelength division multiplexing EDC electronic disp
38、ersion compensation EIA Electronic Industries Alliance IEEE Institute of Electrical and Electronics Engineers FDM frequency division multiplexing FEC forward error correction FFE feed-forward equalizer ISI inter-symbol interference ITU International Telecommunication Union LAN local area network LED
39、 light emitting diode MDCF modal dispersion compensating fiber MLSD maximum likelihood sequence detection MMF multimode fiber MPN mode partition noise MPO Multi-position Push-On MN modal noise MUX multiplexer NRZ non-return-to-zero OC optical carrier OFDM orthogonal frequency division multiplexing O
40、IF Optical Internetworking Forum OM3 optical multimode 3 OM4 optical multimode 4 PIN positive-intrinsic-negative PMD Physical Media Dependent RIN relative intensity noise RS Reed-Soloman Rx receiver SAN storage area network SDM space division multiplexing TIA Telecommunications Industry Association
41、TRX transceiver Tx transmitter TSB Telecommunications System Bulletin UI unit interval VCSEL vertical cavity surface emitting laser VSR very short reach WDM wavelength division multiplexing ZDW zero dispersion wavelength 3.3 Units of Measure TIA TSB-172-A 4 dB decibel ft feet, footGb/s gigabits per
42、second Gbaud giga baud in inch km kilometer Mb/s megabits per second MHzkm megaHertzkilometer m meter mm millimeter m micrometer or micron nm nanometer 4 SOME TRANSMISSION TECHNIQUES AND TECHNOLOGIES 4.1 General The purpose of a digital transmission system is to propagate information, with acceptabl
43、y low bit error ratio (BER), between a transmitting device and a receiving device. As illustrated in Figure 1, information flows through digital transmission systems from a binary source, to an optional encoder that inserts error detecting/correcting information and/or framing information and/or tim
44、ing (e.g. transition density) and spectral shaping content, to a line coder that converts the binary bits into symbols with the desired modulation characteristics, to a transmitter that modulates the symbols into some form of energy compatible with the transmission medium, to a transmission medium t
45、hat conveys the energy, to a receiver that detects the energy and recovers the symbols, to a line decoder that converts the symbols into binary bits, to an optional decoder that detects and/or corrects transmission errors while extracting the original binary information, to a binary data sink such a
46、s a memory device. Figure 1 Block diagram of digital transmission system In multimode fiber transmission systems, lasers are commonly used as transmitters at channel rates above 500 Mb/s, multimode fiber is the medium, and PIN (positive-intrinsic-negative) photodiodes are commonly used as detectors
47、in the receiver. Encoding with block codes is common, as is the use of binary amplitude shift key (i.e. on-off) modulation. The available system gain, which is the difference between the minimum transmitter modulation power and the minimum receiver modulation sensitivity, is apportioned to various p
48、urposes forming the channel power budget as diagrammed in Figure 2. Two impairments typically optional encoderbinary data source line coder transmittertransmission mediumreceiverline decoderoptional decoderbinary data sinkTIA TSB-172-A 5 consume the majority of the available power budget in multimod
49、e fiber transmission systems: attenuation and dispersion, which is one of the distortion impairments. Attenuation diminishes the signal power through absorption, scattering and coupling losses, while dispersion spreads symbols outside their allocated time interval. Various noise impairments related to laser-based transmission and signal distortions caused by jitter also degrade the signal, but usually to a lesser degree. Figure 2 Channel power budget Figure 3 illustrates the changes in the transmitted waveform due to attenuation and dispersion eff
