CN102480320A - Real-time position measuring method for optical fiber fault points - Google Patents
Real-time position measuring method for optical fiber fault points Download PDFInfo
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- CN102480320A CN102480320A CN2010105571627A CN201010557162A CN102480320A CN 102480320 A CN102480320 A CN 102480320A CN 2010105571627 A CN2010105571627 A CN 2010105571627A CN 201010557162 A CN201010557162 A CN 201010557162A CN 102480320 A CN102480320 A CN 102480320A
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Abstract
The invention relates to a real-time position measuring method for optical fiber fault points, which relates to the field of optical fiber communication and is used for reducing cost and time of optical fiber fault maintenance. The real-time position measuring method mainly comprises following functional modules: including a high-precision time synchronization module, a high-precision alarming time recording module and a fault point position calculating module. During operation, periodic synchronization of time of each two nodes can be guaranteed and transmission delay between the two nodes can be measured by means of time synchronization protocols (such as a 1588v2 protocol) of the high-precision time synchronization module. The high-precision alarming time recording module is capable of accurately recording arrival time of a signal affected by the fault points to a receiver by means of functions of rapid alarming triggering and alarming trigger delay compensation. The fault point position calculating module is used for calculating specific positions of fault points according to information acquired by the high-precision time synchronization module and the high-precision alarming time recording module about the two nodes.
Description
Technical field
The invention belongs to communication system line upkeep field of measurement, relate to both-way communication system line abort situation method of measurement, be specifically related to utilize bidirectional optical fiber system transmissions signal in real time accurately to measure the method for fiber failure point position between two nodes.
Prior art
Existing mainstream technology is to adopt optical pulse time domain reflection technology measuring optical fiber position of failure point, and the optical time domain reflectometer structure is shown in figure one.The optical time domain reflectometer test, receives the information of returning at the optical time domain reflectometer port then and carries out in optical fiber through the emission light pulse.When light pulse is transmitted in optical fiber, can be because the character of optical fiber itself, connector, the junction point, crooked or other similar incident and produce scattering reflects.Wherein the scattering of a part will turn back in the optical time domain reflectometer with reflection.The useful information that returns is measured by the detector of optical time domain reflectometer, and they are just as time on the diverse location in the optical fiber or curve segment.From transmitting signals to the used time of inverse signal, confirm the speed of light in glass substance again, just can calculate distance.Below formula just explained that optical time domain reflectometer is a measuring distance how:
d＝(c×t)/2(IOR)
In this formula, c is a light speed in a vacuum, and t is that signal emission back is to the total time that receives signal (round trip) (it is exactly the distance of one way that two values multiply each other after 2).The speed of light in optical fiber is relevant with optical fibre refractivity (IOR).IOR is indicated by the optical fiber production merchant.
Optical time domain reflectometer uses Rayleigh scattering and Fresnel reflection to characterize the characteristic of optical fiber.Rayleigh scattering is to form owing to light signal produces irregular scattering along optical fiber.Optical time domain reflectometer is just measured a part of scattered light of getting back to the optical time domain reflectometer port.These backscatter signals have just shown decay (loss/distance) degree that is caused by optical fiber.The track that forms is a downward curve, and it has explained that the power of backscattering constantly reduces, and this is owing to all losses to some extent of signal through emission and backscattering after the transmission of a segment distance.Given behind the optical fiber parameter, the power of Rayleigh scattering just can be indicated out, if wavelength is known, it is just proportional with the pulse duration of signal: pulse duration is long more, and backscattering power is just strong more.The power of Rayleigh scattering is also relevant with the wavelength that transmits, and wavelength is short, and then power is stronger.That is to say that the track that produces with the 1310nm signal can be higher than the rayleigh backscattering of the track that 1550nm signal produced.
At high wavelength zone (surpass 1500nm), Rayleigh scattering can continue to reduce, but another one makes the phenomenon of infrared ray decay (or absorption) to occur, and increases and caused the increase of whole pad values.Therefore, 1550nm is minimum decay wavelength; This has explained also why it is the wavelength as long haul communication.Very natural, these phenomenons also can have influence on optical time domain reflectometer.As the optical time domain reflectometer of 1550nm wavelength, it also has low fade performance, therefore can grow the test of distance.And as high 1310nm or 1625nm wavelength of decaying, the measuring distance of optical time domain reflectometer just must be restricted, because testing equipment need be measured a sharp cutting edge of a knife or a sword in the optical time domain reflectometer track, and the tail end of this sharp cutting edge of a knife or a sword can drop in the noise apace.
Rayleigh scattering is to form owing to light signal produces irregular scattering along optical fiber.Optical time domain reflectometer is just measured a part of scattered light of getting back to the optical time domain reflectometer port.These backscatter signals have just shown decay (loss/distance) degree that is caused by optical fiber.Fresnel reflection is the reflection of dispersing, and it is caused that by the individual point in the whole piece optical fiber these points are made up of the factor that causes reverse parameter to change, for example the gap of glass and air.On these aspects, have very strong back-scattering light and be reflected.Therefore, optical time domain reflectometer is exactly to utilize the information of Fresnel reflection to be located by connecting some fibre-optic terminus or breakpoint.
The operation principle of optical time domain reflectometer just is similar to a radar.It earlier sends a signal to optical fiber, and what information is observed then and a bit returns what come from certain is.This process can repeatedly be carried out, and then these results is averaged and shows that with the form of track this track has just been described the power of signal in whole section optical fiber.
Goal of the invention
The advantage of optical pulse time domain reflection technology is the decay and the reflecting properties that can intuitively reflect each point in the fibre circuit, can single-spot testing.Deficiency mainly contains 2 points: at first optical time domain reflectometer is according to the test light pulse signal work that receives reflection; If transmit the work light signal in the optical fiber simultaneously; Work light also will produce emission; Test result to optical time domain reflectometer produces interference, and optical fiber connects in the time of need changing normal transmission when therefore testing, and builds test platform and measures.Next adopts the optical pulse time domain reflection technology can't penetrate the fiber amplifier in the transmission line.Usually optical fiber amplification node is positioned at the suburb, does not have personnel and test instrumentation on duty.Optical fiber breaks down between node when two optical fiber amplify, and need want the attendant to carry optical time domain reflectometer to amplifying node test fault origination point position usually, consuming time generally several hours to a couple of days, fiber failure safeguarded brings a lot of inconvenience.At present the up-to-date progress of research field also has the Time Domain Reflectometry technology is provided with wavelength separately; Be integrated in the light communication system to realize real-time monitoring through WDM technology; But, fail to be applied because cost does not effectively solve with the problems such as interference of measurement wavelength to operation wavelength.This research direction still can not solve the problem that penetrates fiber amplifier of measuring simultaneously.The present invention will solve the problem that influences communications when line fault point position can not be measured in real time and measure; Realize when line fault occurs; The system maintenance personnel not only can know through NMS at once, and fault has taken place; The position that fault takes place be can also know, time and cost that communication system is safeguarded effectively reduced.
Summary of the invention
For overcoming the prior art shortcoming of measuring optical fiber position of failure point in real time; On the basis that makes full use of functions such as existing communication system circuit, split-second precision synchronizing function and high accuracy alarm timing; A kind of low cost of the communication system self performance not being had influence is provided; The method that high-precision fiber failure point position is measured in real time reduces cost and preventive maintenance time that fiber failure is safeguarded.
The present invention mainly comprises following functional module: split-second precision synchronization module, high accuracy alarm time logging modle and position of failure point computing module.
The time synchronization protocol (like the 1588v2 agreement) that split-second precision synchronization module communication system capable of using self is supported to be guaranteeing that time cycle property is synchronous between two nodes, and measures two internodal transmission delays, for the fault point measurement provides benchmark.
High accuracy alarm time logging modle provides the precise time of split-second precision synchronization module in synchronizing cycle through high-speed counter; And support quick alarm triggered and alarm triggered compensation of delay, but the signal that accurate recording is influenced by the fault point arrives the time of receiver.
The information that the position of failure point computing module is collected through the split-second precision synchronization module and the high accuracy alarm time logging modle of two nodes can calculate the distance of fault point from this node.
The principle of the invention is following: during the Fiber Optical Communication System operate as normal, be full of transmission signals in the fibre circuit; When the fibre circuit point broke down, the signal through the fault point did not receive fault effects, still can ensure signal quality, and fault the optical signals of back through the fault point took place in influenced by the fault point, and signal quality is with deterioration.Because line fault influences forward and reverse signal of communication usually simultaneously, quick switch fault report mechanism and alarm compensation of delay through receiver can obtain forward and reverse deterioration signal and arrive the receiving terminal precise time.Receive the transmission speed of signal in time that deterioration signal arrives and the optical fiber through two end nodes, can calculate the accurate distance of fault origination point to two end nodes.
Description of drawings
Accompanying drawing 1 is the existing optical time domain reflection technology measuring optical fiber abort situation functional module structure sketch map that adopts.
Accompanying drawing 2 is real time fail point position monitoring system function module structural representations that the present invention proposes.
Implementation method
The concrete job step of explanation shown in Fig. 2 bidirectional optical fiber transmission system:
1.A node sends to the B node with own local zone time Ta1, returns response signal to the A node at once after the B node is received.
2.A nodes records can obtain the transmission delay (Ta2-Ta1)/2 of A to B, and this time-delay and A local zone time are sent to the B node once more to receiving B node response signal time T a2.
3.B node is revised own local zone time according to time that receives the transmission of A node and time-delay and the A node time is synchronous.
4. optical fiber is when fault appears in the D point constantly as Td, and to the data that the A node sends, there is normal flow T2 in the DA section, but follow-up for receiving the fault effects deterioration signal from the B node; To the data that the B node sends, there is normal flow T2 in the DB section, but follow-up for receiving the fault effects deterioration signal from the A node;
5. after the A point is received T2, will receive deterioration signal, A node fast recording receives deterioration signal, i.e. the time point t2 of the last 1bit of T2 is as the time of failure of local record.
6. in like manner can note the time point t1 that the B point receives the last 1bit of T1, as the time of failure of local record.
7. can obtain the time-delay Tad that D point in fault point orders to A does
Tad＝((t2-t1)+t)/2
8. can obtain the time-delay Tad that D point in fault point orders to B does
Tbd＝((t1-t2)+t)/2
9. can obtain by fiber transmission speeds s=3E8/ optical fibre refractivity
10. can obtain the distance that D point in fault point orders to A does
Lad＝Tad*s
11. can obtain the distance that D point in fault point orders to B do
Lbd＝Tbd*s
Optical fiber is positioned at the two fine bilateral system (comprise band fiber amplifier system) of same cable run, because the fault point acts on the whole piece cable run usually simultaneously, the aforementioned calculation method is suitable equally.
Claims (3)
1. real-time accurate measurement method to circuit position of failure point between the fiber optic transmission system node, it is characterized in that: in the bidirectional optical fiber communication system, this method includes the following step:
(1) adopts synchronous two node times of split-second precision simultaneous techniques through the time synchronized module, and obtain two internodal transmission delays; As adopting split-second precision agreement such as 1588v2, the time deviation of two nodes can be less than 10ns;
(2) nodes records local node in two ends receives the time that receives the fault effects signal, as recorder signal generation signals lose, time of Signal Degrade state such as Frame Alignment Loss or error code number are out-of-limit, as local time of failure; Like direct employing signal alarm time of origin,, realize that nodes records receives this fault effects signal to arrive the node time precision and reaches the ns rank through the retention time that the local compensated receiver of node triggers alarm;
(3) receive the fault effects signal to arrive node time (t1, t2) and two internodal transmission delays (t) according to signal in transmission speed (s), two nodes records of transmission line, calculate the distance of fault origination point to two nodes.
The time-delay Tad that D point in fault point is ordered to A is: Tad=((t2-t1)+t)/2
The time-delay Tad that D point in fault point is ordered to B is: Tbd=((t1-t2)+t)/2
The distance that D point in fault point is ordered to A: Lad=Tad*s
The distance that D point in fault point is ordered to B: Ldb=Tdb*s
2. method of measurement according to claim 1 is characterized in that: before fault took place, system was in normal transmission and receiving state signal; And through split-second precision synchronization module precise synchronization two node times and record two internodal transmission delays; When fault took place, two end nodes accurately record received the fault effects signal to arrive the time of local node.And through quick malfunction monitoring and local compensation assurance Measuring Time precision reference.
3. monitoring method according to claim 1 is characterized in that: this method of measurement is suitable for various optical cable point-to-point line transmission systems, and part is put the multiple spot optical transmission system; For the point-to-point Frequency Division Multiplexing system, (wavelength-division multiplex system) only needs one of them channel (wavelength) effectively to measure, and precision and single-frequency/single wave system system is just the same; For putting multiple spot Frequency Division Multiplexing system (like WDM PON system), need that then it is decomposed into a plurality of point-to-point transmission links and consider, and every point-to-point transmission link all need be supported this method of measurement; For putting multiple spot time division multiplex system (like GPON, EPON), its certainty of measurement receives the influence in ascending time slot cycle.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014101668A1 (en) * | 2012-12-26 | 2014-07-03 | 中兴通讯股份有限公司 | Time synchronization processing method and apparatus |
| CN105865750A (en) * | 2016-05-25 | 2016-08-17 | 成都英鑫光电科技有限公司 | Optical fiber defect detecting method and device |
| CN108900244A (en) * | 2018-06-27 | 2018-11-27 | 电子科技大学 | A kind of FC optical interface data and its method of related data monitoring and test |
-
2010
- 2010-11-24 CN CN2010105571627A patent/CN102480320A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014101668A1 (en) * | 2012-12-26 | 2014-07-03 | 中兴通讯股份有限公司 | Time synchronization processing method and apparatus |
| CN105865750A (en) * | 2016-05-25 | 2016-08-17 | 成都英鑫光电科技有限公司 | Optical fiber defect detecting method and device |
| CN108900244A (en) * | 2018-06-27 | 2018-11-27 | 电子科技大学 | A kind of FC optical interface data and its method of related data monitoring and test |
| CN108900244B (en) * | 2018-06-27 | 2021-02-26 | 电子科技大学 | FC optical interface data and related data monitoring and testing method thereof |
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Application publication date: 20120530 |