[go: up one dir, main page]

WO2011051930A1 - Technique de localisation de défaillance dans des réseaux optiques passifs - Google Patents

Technique de localisation de défaillance dans des réseaux optiques passifs Download PDF

Info

Publication number
WO2011051930A1
WO2011051930A1 PCT/IL2010/000827 IL2010000827W WO2011051930A1 WO 2011051930 A1 WO2011051930 A1 WO 2011051930A1 IL 2010000827 W IL2010000827 W IL 2010000827W WO 2011051930 A1 WO2011051930 A1 WO 2011051930A1
Authority
WO
WIPO (PCT)
Prior art keywords
optical
splitter
splitters
passive
level
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/IL2010/000827
Other languages
English (en)
Inventor
Ido Ouzieli
Amitay Melamed
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ECI Telecom Ltd
Original Assignee
ECI Telecom Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ECI Telecom Ltd filed Critical ECI Telecom Ltd
Publication of WO2011051930A1 publication Critical patent/WO2011051930A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
    • G01M11/30—Testing of optical devices, constituted by fibre optics or optical waveguides
    • G01M11/31—Testing of optical devices, constituted by fibre optics or optical waveguides with a light emitter and a light receiver being disposed at the same side of a fibre or waveguide end-face, e.g. reflectometers
    • G01M11/3109—Reflectometers detecting the back-scattered light in the time-domain, e.g. OTDR
    • G01M11/3136—Reflectometers detecting the back-scattered light in the time-domain, e.g. OTDR for testing of multiple fibers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/071—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using a reflected signal, e.g. using optical time domain reflectometers [OTDR]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
    • H04B10/0791—Fault location on the transmission path
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/14—Monitoring arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/44—Star or tree networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062—Network aspects
    • H04Q11/0067—Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062—Network aspects
    • H04Q2011/0079—Operation or maintenance aspects
    • H04Q2011/0083—Testing; Monitoring

Definitions

  • the invention relates to a technology for localization faults in passive optical networks (PONs), an in particular - to probing and testing techniques utilizing Passive Optical Splitters.
  • PONs passive optical networks
  • Passive Optical Splitters
  • Any PON network is based on a central OLT (Optical Line Termination) that is connected to a group of ONTs (Optical Network Terminals) via a tree-like optical network formed by optical fibers, where OLT is positioned at the root of the tree.
  • OLT Optical Line Termination
  • ONTs Optical Network Terminals
  • Each branch in the PON tree is divided to several "smaller" branches by means of Passive Optical Splitters, and each of the last branches (or leaves) is connected to an ONT, one ONT per leave.
  • Fig. 1 illustrates quite a typical type of passive optical networks, where a single splitting level is used for connecting a number N of Optical Network Terminals (ONTs) 12 to the Optical Line Termination (OLT) 10.
  • ONT Optical Line Termination
  • a single 1 :N Passive Optical Splitter 14 is used, where N is equal to the number of ONTs.
  • the 1 :N Passive Optical Splitter is physically built in the form of a cascade comprising multiple layers of 1 :2 passive optical splitters.
  • Fig. 2a schematically illustrates the physical structure of the basic components of the splitter 14.
  • Each 1 :2 passive optical splitter 16 is actually built from optical fiber sections as a 2:2 splitter having four fiber ends (two at each side of the splitter) where one of its ends ( marked 18) is not in use.
  • an optical splitter/coupler comprises two optical fibers, fused together along a portion of the lengths thereof to form a coupling region. Consequently, the 1 :2 optical splitter physically behaves as a 2:2 splitter, i.e., an optical signal applied to any of its ends at one side of the splitter will be divided into two optical signals (with 1/2 of the original power) appearing at two ends at the opposite side of the splitter.
  • any of the downstream and upstream signals is divided into 2 signals (each having only a half of power of the original signal). Since only a single upstream branch facing the OLT 10 is used in the splitter 16, it means that only 1/2 of power of any upstream optical signal will actually reach the OLT in the 1 :2 splitter "made from" the original 2:2 splitter.
  • Fig. 3 illustrates a 1 : 16 Passive Optical Splitter 30 comprising a cascade of four levels of 1 :2 passive Optical-Splitters: the first level with a single splitter to be connected to OLT 10, the second level with two splitters receiving the signal split by the single splitter of the first level, the third level with four splitters pair-wise connected to the two splitters of the second level, and the fourth level with eight splitters together serving sixteen clients (ONTs 12).
  • At each split level at least 1/2 of the initial incoming power is lost in a splitter in the upstream direction from a specific ONT towards the OLT 10.
  • At each split level at least 1/2 of the initial incoming power is divided equally between both ends of a splitter in the downstream direction from the OLT 10 to a specific ONT. Indeed, the power of a signal transmitted by OLT 10 downstream or upstream via link 31 , is divided by 2 at each splitter on the way, and finally the signal's power becomes N-times reduced by the cascade of optical splitters.
  • an Optical Time-Domain Reflectometer (OTDR, 14) can be utilized, which is usually located at the OLT 10 premises and issues an initial probe signal towards ONTs 12. The signal is reflected back from each of the ONTs towards the OTDR 14. The return signal received at the OTDR 14 will actually be a sum of all returning signals from all branches. Each single return signal has very low power, as it lost (N- l)/N of its power on the way down, and after that (N-l) N of its power on the way up. Therefore, the returning signal (per branch) is 1/N 2 of the original OTDR signal. In such a situation, extremely high sensitivity is required from the Receiver of the OTDR 14.
  • a further problem occurs when a rogue/faulty ONT starts constantly transmitting in the upstream direction.
  • the OLT 10 has no means for distinguishing the faulty ONT, and this is due to the fact that in PON networks the single interface at that OLT is shared by all other ONTs, and no differentiation means are available.
  • US 2008031624 A describes an Optical Time-Domain Reflectometer OTDR, which allows enhancing troubleshooting of a passive optical network (PON) by deploying cascaded splitters, at least some of which have multiple inputs. That is, at least some of the splitters in the PON have not only a first input coupleable to the optical line terminator (OLT) or an output of another splitter, but also a second input directly coupleable to an Optical Time-Domain Reflectometer (OTDR).
  • Optical time-delay reflectometry can be performed upon a selected portion or segment of the PON by selecting a splitter and transmitting an optical test signal from the OTDR directly to the input of the selected splitter and analyzing the reflected signal.
  • each splitter of the cascade is a "free-standing" one and, thereby, a signal from OTDR can physically be input to the specific splitter which has to be checked; the response signal is thus received from all the ONTs that are mapped/appended to that specific splitter. If the number of such ONTs is more than two, the exact localization of fault remains problematic.
  • the response signal cannot be mixed with responses from different splitters, the problem of fault localization in PON networks remains not resolved at least for cases where a group of ONTs is connected to any common point in a network via an integrated cascaded splitter (i.e., where there is no outside access ends to inputs of specific splitters of the cascade). In this case, differentiation between ONTs that are connected to the same splitter is impossible.
  • the Inventor proposes a new Passive Optical Splitter, which adds a simple low-cost capability to existing Passive splitters.
  • the 1 :N passive optical splitter would have at least l+N/2 upstream interfaces.
  • the first interface (“ 1 ", positioned at the root of the cascade) would carry the sum of all upstream traffic signals from all ONTs, where the power per ONT would be of about 1 N of its original power.
  • the additional "N/2" interfaces are the previously unused, probing ends of the splitters at the lowest level of the cascade.
  • Each such additional “probing” interface carries the sum of upstream traffic from one pair of ONTs, where the power per ONT, on the probing end, is of about 1/2 of ONT's original power.
  • an integrated, self-contained probe device accommodating in its housing a cascaded 1 :N passive optical splitter having a tree-like form and comprising an optical passive splitter ( say, a 1 :2 optical passive splitter) at a root level of the tree, and a group including N/2 of optical passive splitters at a leaves' level of the tree;
  • each of said N/2 passive optical splitters having three working ends and one free probing end, and being adapted to carry, via the working ends thereof, optical signals to and from a pair of outside entities, so that said N/2 splitters are adapted to serve N outside entities (optical network devices or optical network portions);
  • the integrated probe device being characterized in that the free probing ends of said N/2 optical splitters extend out of the housing of said integrated probe device and are adapted for testing purposes, more specifically for testing said N entities.
  • the passive optical splitters of said group can be called 1 :2 splitters each comprising a fourth, previously unused end which is now utilized as a probing end extends outside. Alternatively, they can be called and just be 2:2 splitters where one of the ends is used as a probing end.
  • An OTDR device can be used with the proposed 1 :N splitter as follows: OTDR sends its original testing signal downstream via the free outbound interface of a specific 1 :2 splitter (preferably, of the lowest leaves' level), and then receives from that same 1 :2 splitter a return upstream signal representing two ONTs connected to that splitter.
  • additional outbound upstream interfaces can be freed and utilized at intermediate level(s) of the integral splitter, thus allowing connection of the OTDR to them and thereby achieving a self-checking property of the integral splitter.
  • the described N/2 "probing" interfaces of the lower level can be connected, say, to a mechanical switch, for selectively switching these interfaces to the OTDR.
  • a mechanical switch for selectively switching these interfaces to the OTDR.
  • the 1 :N passive splitter with the described functionality can be used for testing any other network element or network portion switched to the splitter instead of any particular ONT of group.
  • each link connected/ available for being connected to the testing equipment carries upstream traffic transmission representing only two ONTs/network portions (instead of all ONTs in the prior art).
  • This fact essentially simplifies the OTDR fault localization algorithm.
  • the power of each single return signal from a specific ONT is much higher than in the prior art (i.e., on the optical link leading to OLT), since the single return signal loses only 1/2 of its power on the way down and up, instead of losing (N- l)/N of its power in the prior art (per direction). Therefore, the returning signal (per branch) is 1/4 of the original OTDR signal (instead of 1/N 2 ). For the above case of 16 ONTs it means 1/4 instead of 1/256.
  • the testing system for testing N optical network entities may comprise :
  • testing equipment such as OTDR unit
  • OTDR unit connected directly or indirectly to one ore more free probing ends of the N/2 leaves' level optical splitters, and being capable of testing said N optical network entities via said N/2 optical splitters.
  • the optical network may be an xPON network, but may, for example, be ONT.
  • Fig. 1 (prior art). Is one basic configuration of a PON network utilizing an 1 :N passive optical splitter
  • FIG. 2a (prior art).
  • a 2:2 optical splitter/coupler formed by fusing two optical fibers.
  • FIG. 2b (priori art).
  • a passive 1 :2 optical splitter formed from a 2:2 passive optical splitter of Fig. 2a.
  • FIG. 3 (prior art).
  • Fig. 4 shows one embodiment of the proposed probe device based on the 1 :N optical splitter
  • Fig. 5 illustrates one embodiment of a testing system comprising the probe device of Fig. 4.
  • Fig. 4 illustrates one embodiment of the proposed integrated 1 :N splitter (N>2) for a PON network.
  • N 16
  • the splitter 40 is a 1 : 16 cascaded integrated splitter, comprising one root level 1 :2 splitter 41 , splitters of intermediate levels, and eight (N/2) 1 :2 splitters 42 of the lower, leaves' level.
  • the root splitter 41 is connected via one of its working end to OLT 43, and the splitters 42 are connected to sixteen ONTs 44.
  • the 1 :2 splitters 42 if not all splitters in the device 40, are manufactured as 2:2 splitters, where one of the ends (namely, end 45) of each particular splitter is not used for carrying optical data signals, but intended for serving as a probing end.
  • all such ends 45 extend from the integrated body of the splitter 40 and form a plurality (bundle) of probing ends 46 which can be connected to any type of testing equipment, for selectively testing the splitters 42 and the corresponding network portions (in this case, ONTs 44) connected to the splitters 42.
  • one or more other splitters in the cascade splitter 40 can be manufactured with the probing ends extending outside (like the probing end 47 of one intermediate level splitter in Fig. 4).
  • Fig. 5 illustrates one embodiment of a testing system 50 comprising the cascaded 1 :N splitter 40 connected, through a probing bundle 46, to an OTDR unit 52 via a switch 54.
  • the probing ends bundle 46 comprises at least two additional probing ends from different splitting levels of the device 40.
  • a controllable mechanical switch is utilized, which is able to successively connect one or another splitter to the OTDR 52.
  • OTDR issues a testing signal to one splitter at a time, (say, to splitter 42' via its probing end 45' downstream) and then receives a reflected upstream testing signal from the splitter via the same probing end (45').
  • the reflected testing signal received by the OTDR 52 at sufficiently high power clearly characterize the status of the splitter, the equipment connected to the splitter and the interconnecting fibers.
  • the OTDR unit may test another splitter of the device 40.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • Signal Processing (AREA)
  • Electromagnetism (AREA)
  • Optics & Photonics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optical Communication System (AREA)

Abstract

L'invention concerne un dispositif à sonde intégrée renfermant un répartiteur optique passif 1 :N en cascade qui présente une structure arborescente et qui comporte, à la racine de l'arborescence, un répartiteur optique passif, et, au niveau des feuilles de l'arborescence, un groupe comprenant des répartiteurs passifs optiques N/2. Dans ce dispositif à sonde, les extrémités de sondage des répartiteurs passifs optiques N/2 s'étendent à partir dudit dispositif à des fins de test.
PCT/IL2010/000827 2009-10-27 2010-10-12 Technique de localisation de défaillance dans des réseaux optiques passifs Ceased WO2011051930A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IL201773 2009-10-27
IL201773A IL201773A0 (en) 2009-10-27 2009-10-27 Technique for fault localization in passive optical networks

Publications (1)

Publication Number Publication Date
WO2011051930A1 true WO2011051930A1 (fr) 2011-05-05

Family

ID=42263446

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IL2010/000827 Ceased WO2011051930A1 (fr) 2009-10-27 2010-10-12 Technique de localisation de défaillance dans des réseaux optiques passifs

Country Status (2)

Country Link
IL (1) IL201773A0 (fr)
WO (1) WO2011051930A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013025979A3 (fr) * 2011-08-17 2013-05-10 Tyco Electronics Corporation Réseaux optiques passifs distribués
WO2016138297A1 (fr) * 2015-02-26 2016-09-01 Commscope Technologies Llc Architecture d'antenne distribuée
US10317639B2 (en) 2016-11-11 2019-06-11 CommScope Connectivity Belgium BVBA Fiber optic network architecture

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5452075A (en) * 1992-07-03 1995-09-19 Telefonaktiebolaget Lm Ericsson Method and device for monitoring branched optical line network
US20080031624A1 (en) 2006-08-01 2008-02-07 Smith Joseph Lee Passive optical network optical time-domain reflectometry

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5452075A (en) * 1992-07-03 1995-09-19 Telefonaktiebolaget Lm Ericsson Method and device for monitoring branched optical line network
US20080031624A1 (en) 2006-08-01 2008-02-07 Smith Joseph Lee Passive optical network optical time-domain reflectometry

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013025979A3 (fr) * 2011-08-17 2013-05-10 Tyco Electronics Corporation Réseaux optiques passifs distribués
US9739945B2 (en) 2011-08-17 2017-08-22 Commscope Technologies Llc Distributed passive optical networks
US10551565B2 (en) 2011-08-17 2020-02-04 Commscope Technologies Llc Distributed passive optical networks
US11675131B2 (en) 2011-08-17 2023-06-13 Commscope Technologies Llc Distributed passive optical networks
WO2016138297A1 (fr) * 2015-02-26 2016-09-01 Commscope Technologies Llc Architecture d'antenne distribuée
US10560211B2 (en) 2015-02-26 2020-02-11 Commscope Technologies Llc Cable arrangement with wavelength division multiplexer
US11012176B2 (en) 2015-02-26 2021-05-18 Commscope Technologies Llc Cable arrangement with wavelength division multiplexer
US11705980B2 (en) 2015-02-26 2023-07-18 Commscope Technologies Llc Cable arrangement with wavelength division multiplexer
US10317639B2 (en) 2016-11-11 2019-06-11 CommScope Connectivity Belgium BVBA Fiber optic network architecture

Also Published As

Publication number Publication date
IL201773A0 (en) 2010-06-16

Similar Documents

Publication Publication Date Title
US7715718B2 (en) Passive optical network optical time-domain reflectometry
CN101291176B (zh) 一种光分布网络的故障检测方法、系统及装置
KR101657329B1 (ko) 수동 광통신 망에서 오류를 발견하기 위한 방법과 장치
US8948589B2 (en) Apparatus and method for testing fibers in a PON
US6980287B2 (en) System for testing an optical network using optical time-domain reflectometry (OTDR)
CN101826919B (zh) 一种混合型无源光网络及其故障定位和恢复的方法
JP6253659B2 (ja) センサを備えるファイバネットワーク
CN102035599A (zh) 一种ftth无源光链路监测系统及方法
CN103548287A (zh) 波分复用光网络的监管
US11290203B2 (en) Circuitry for remote optical communications devices and methods utilizing same
WO2012097554A1 (fr) Terminal de ligne optique, système de réseau optique passif et procédé de transmission de signaux optiques
CN102377486B (zh) 一种监测pon光链路中非反射型故障的系统
CN102594452A (zh) 一种自诊断无源光网络系统
CN103222206B (zh) 分支光纤的故障检测方法、装置及系统
KR20130029329A (ko) 분산제어형 광선로 감시방법 및 측정장치
CN201918994U (zh) Ftth无源光链路监测系统
US8014670B2 (en) Method and apparatus for testing and monitoring data communications in the presence of a coupler in an optical communications network
WO2011051930A1 (fr) Technique de localisation de défaillance dans des réseaux optiques passifs
TW201023536A (en) Optical network monitoring system and method
JP4383162B2 (ja) 光分岐線路監視システム
CN106100746B (zh) 一种用于otdr光纤检测的测试波中继设备及其控制方法
CN110518966A (zh) 一种基于正交编码的onu定位系统和定位方法
CN108462530B (zh) 一种光线路终端测试装置
EP4175196B1 (fr) Procédé et système de mise en oeuvre d'un point de démarcation entre un réseau fournisseur et un réseau client
KR100817495B1 (ko) 감시광 루핑 방법을 이용한 피오엔 원격 광선로망 감시장치

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 10785227

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 10785227

Country of ref document: EP

Kind code of ref document: A1