CN104426602B - A kind of fiber optical time domain reflection instrument - Google Patents
A kind of fiber optical time domain reflection instrument Download PDFInfo
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- CN104426602B CN104426602B CN201310380182.5A CN201310380182A CN104426602B CN 104426602 B CN104426602 B CN 104426602B CN 201310380182 A CN201310380182 A CN 201310380182A CN 104426602 B CN104426602 B CN 104426602B
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Abstract
The invention discloses a kind of fiber optical time domain reflection instrument, described device includes：Trigger, laser, attenuator, circulator, upper conversion single-photon detector and time-to-digit converter, OTDR in the present invention uses upper conversion single-photon detector, upper conversion single-photon detector uses 1900nm to 2000nm pump wavelength, pair and frequency light carry out narrow-band filtering, the NEP lower than classical detector is obtained under identical quantum efficiency, its NEP value can reach 140dbm, because NEP value is lower, the dynamic range detected is bigger, upper conversion single-photon detector effectively increases the dynamic range that OTDR can be measured, improve the resolution ratio of detection, reduce time of measuring, effectively avoid the blind area occurred after Fresnel reflecting peak.
Description
Technical field
The present invention relates to fiber optic communication field, more particularly to a kind of fiber optical time domain reflection instrument.
Background technology
At present, continuing to develop with optic communication, an important branch --- Fibre Optical Communication Technology in optic communication
（Optical Fiber Communications）The advantages of with its transmission frequency bandwidth, high anti-interference and small signal attenuation, by
The gradually transmission means such as replacement cables, microwave communication, as prevailing transmission mode in world communication.Fiber optic communication is made using light wave
Carrier wave, reaches information using optical fiber as transmission medium the communication mode at another place at one, is referred to as " wired " optic communication.
Therefore, the quality of optical fiber property directly affects the speed and distance of optical signal transmission.
Situations such as thunder and lightning, earthquake and construction, is easily caused the damage of optical fiber, causes the interruption of optic communication.In order to reduce damage
Lose, the optical fiber for diagnosing, repairing damage in time is particularly important.Fiber optical time domain reflection instrument（Optical Time-Domain
Reflectometer, OTDR）According to the back scattering of light and Fresnel inversion principle, produced when being propagated in a fiber using light
Rear orientation light obtain the information of attenuated optical signal, available for measurement optical fiber attenuation and splicing loss, positioning optical fiber therefore
Hinder point, loss distribution situation of the analysis optical fiber along length etc., essential instrument in being optical cable construction, maintenance and monitoring.
Traditional OTDR systems mainly use classical photo-detector, for example：Photomultiplier under linear model
（Photomultiplier Tube, PMT）, PIN photodiode and avalanche photodide（Avalanche Photo
Diode, APD）Signal Deng the output of, photo-detector is proportional to the size of Rayleigh reflective light intensity.
When those skilled in the art diagnose optical fiber using above-mentioned OTDR, find to have a disadvantage that：
Dynamic range and noise equivalent power that OTDR can be measured（Noise Equivalent Power, NEP）It is relevant,
NEP values are lower, and the dynamic range that can be measured is bigger.Because classical photo-detector has larger dark current and thermal noise,
OTDR value is generally -110dbm, and the dynamic range for causing OTDR to measure is smaller.
The content of the invention
In view of this, the invention provides a kind of fiber optical time domain reflection instrument, using upper conversion single-photon detector, NEP values
Reachable -140dbm, effectively increases the dynamic range that OTDR can be measured.
A kind of fiber optical time domain reflection instrument, described device includes：
Trigger, laser, attenuator, circulator, upper conversion single-photon detector and time-to-digit converter；
The trigger is used for the electric impulse signal for exporting predeterminated frequency；
The electric impulse signal triggering laser of the trigger output produces the pulse light of identical frequency, the pulse
Flashlight incides the circulator after attenuator decay, and the pulse light exported from the circulator is incided
Detection optical fiber, pulse light obtains back scattering light output to circulator after detection optical fiber Rayleigh scattering, described backward
Scattered light incides upper conversion single-photon detector after circulator is exported；
The upper conversion single-photon detector is used to pump light and the rear orientation light carrying out nonlinear optics and frequency,
Pair and frequency light carry out narrow-band filtering, by after narrow-band filtering and frequency light, to be converted into TTL gate TTL electric signals defeated
Go out, the pump wavelength is 1900nm to 2000nm；
The trigger exports electric impulse signal to time-to-digit converter, and the upper conversion single-photon detector will
TTL electric signal outputs are to time-to-digit converter；
The time-to-digit converter utilizes correspondence on electric impulse signal detection optical fiber position different with TTL electric signal measurements
Photon counting；
Wherein, optical signal passes through polarization maintaining optical fibre between laser, attenuator, circulator and upper conversion single-photon detector
Transmission.
Optionally, the upper conversion single-photon detector includes：
Volume Bragg grating, the Volume Bragg grating be used for pair and frequency light carry out narrow-band filtering.
Optionally,
The size of the Volume Bragg grating is more than or equal to 3.5mm*3.5mm*16mm cube.
Optionally, the trigger includes：
Microwave signal generator and encoder；
The microwave signal generator is used to export inceptive impulse signal；
The encoder is used to encode the inceptive impulse signal, exports the electric impulse signal of predeterminated frequency.
Optionally, the frequency of the inceptive impulse signal of the microwave signal generator output includes：
10GHz。
Optionally,
The laser output power is 1W, and wavelength is 150.12nm, and pulse width is that 50ps is tunable to 10 μ s.
Optionally, the upper conversion single-photon detector includes：
Avalanche silicon diode.
Optionally,
The time jitter jitter of the avalanche silicon diode is 500ps.
Optionally,
Optical signal is transmitted between laser, attenuator, circulator and upper conversion single-photon detector by single-mode fiber；
Then described device also includes：
Polarization Controller, for pump light and the rear orientation light to be adjusted into TM00The polarised light of pattern.
As shown in the above, the method have the advantages that：
The invention provides a kind of fiber optical time domain reflection instrument, with using the classical light such as PMT, PIN and APD in the prior art
The OTDR of detector is different, and the OTDR in the present invention uses upper conversion single-photon detector, and upper conversion single-photon detector is used
1900nm to 2000nm pump wavelength, pair and frequency light carry out narrow-band filtering, obtained under identical quantum efficiency than classics spy
The lower NEP of device is surveyed, its NEP value can reach -140dbm, and because NEP value is lower, the dynamic range detected is bigger, on
Conversion single-photon detector effectively increases the dynamic range that OTDR can be measured, and improves the resolution ratio of detection.
Brief description of the drawings
In order to illustrate more clearly about the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing
There is the accompanying drawing used required in technology description to be briefly described, it should be apparent that, drawings in the following description are only this
Some embodiments of invention, for those of ordinary skill in the art, on the premise of not paying creative work, can be with
Other accompanying drawings are obtained according to these accompanying drawings.
Fig. 1 is a kind of structural representation of fiber optical time domain reflection instrument embodiment one of the invention；
Fig. 2 is a kind of structural representation of fiber optical time domain reflection instrument embodiment two of the invention；
Fig. 3 tests a measurement result schematic diagram for a kind of fiber optical time domain reflection instrument of the invention；
Fig. 4 tests two measurement result schematic diagrames for a kind of fiber optical time domain reflection instrument of the invention；
Fig. 5 tests three measurement result schematic diagrames for a kind of fiber optical time domain reflection instrument of the invention；
Fig. 6（1）For a kind of measurement result schematic diagram of fiber optical time domain reflection instrument experiment 40 of the invention to 120km detection optical fibers；
Fig. 6（2）For a kind of measurement result schematic diagram of fiber optical time domain reflection instrument experiment 4 100 of the invention to 216km detection optical fibers；
Fig. 6（3）Four Fig. 6 are tested for a kind of fiber optical time domain reflection instrument of the invention（2）Schematic diagram after back end reflective peak 602 amplifies；
Fig. 6（4）For a kind of detection optical fiber measurement result schematic diagram of fiber optical time domain reflection instrument experiment 4 100 to 221km of the invention；
Fig. 6（5）Four Fig. 6 are tested for a kind of fiber optical time domain reflection instrument of the invention（4）Schematic diagram after back end reflective peak 603 amplifies；
Fig. 6（6）Four Fig. 6 are tested for a kind of fiber optical time domain reflection instrument of the invention（1）With Fig. 6（2）Result of detection combination diagram；
Fig. 6（7）Four Fig. 6 are tested for a kind of fiber optical time domain reflection instrument of the invention（6）Schematic diagram after back end reflective peak 602 amplifies；
Fig. 6（8）Four Fig. 6 are tested for a kind of fiber optical time domain reflection instrument of the invention（1）With Fig. 6（4）Result of detection combination diagram；
Fig. 6（9）Four Fig. 6 are tested for a kind of fiber optical time domain reflection instrument of the invention（8）Schematic diagram after back end reflective peak 603 amplifies.
Embodiment
The invention discloses a kind of fiber optical time domain reflection instrument, using upper conversion single-photon detector, OTDR systems are realized
The dynamic range of measurement is big, the small advantage of high resolution, measuring section and blind area.
Below in conjunction with the accompanying drawings and the specific embodiment of the invention is described in detail experimental result.
Embodiment one
Fig. 1 is a kind of structural representation of fiber optical time domain reflection instrument embodiment one of the invention, and described device includes：
Trigger 101, laser 102, attenuator 103, circulator 104, upper conversion single-photon detector 105 and time
Digital quantizer 106.
The trigger 101 is used for the electric impulse signal for exporting predeterminated frequency.
Optionally, the trigger 101 includes：Microwave signal generator 107 and encoder 108,
The microwave signal generator 107 is used to export inceptive impulse signal；
The encoder 108 is used to encode the inceptive impulse signal, exports the electric impulse signal of predeterminated frequency.
Explanation is needed exist for, trigger 101 can also can export predeterminated frequency electric impulse signal by others
Equipment is constituted, and is no longer repeated one by one here.
Optionally, the model Agilent N5183A of microwave signal generator, can send 10GHz inceptive impulse signal；
Encoder is the vertical NP1800A of peace, and the electric impulse signal of predeterminated frequency is exported after can initial signal be encoded.
The electric impulse signal triggering laser 102 that the trigger 101 is exported produces the pulse light of identical frequency, institute
State pulse light and incide the circulator 104 after the attenuator 103 decay, exported from the circulator 104
Pulse light incides detection optical fiber.
The trigger 101 is connected with laser 102, and the electric impulse signal of the predeterminated frequency of trigger output is laser
102 trigger signal, triggering laser 102 produces the pulse light of identical frequency.
Optionally, the range of wavelengths of laser 102 is 1900nm to 2000nm, and power output is 1W.Specifically, can be with
Using the QCL-100/200 narrow spaces lasers of quantum communication company, pulse width is tunable from 50ps to 10 μ s, exports pulse
The a length of 150.12nm of signal light-wave.
Because the pulse light peak power that laser is exported is 1W, the power about 250mW needed in detection.Cause
This, pulse light input attenuator 103 is decayed, and is exported after reaching the luminous power needed for detecting to circulator 104.
The circulator 104 is a multiport device, and the transmission of light can only go in ring along one direction, and opposite direction is isolation
's.
The pulse light exported from circulator 104 incides detection optical fiber and detected.
Pulse light obtains back scattering light output to circulator 104 after detection optical fiber Rayleigh scattering, it is described after
Upper conversion single-photon detector 105 is incided after the output of circulator 104 to scattered light.
Rear orientation light incides circulator 104, and upper conversion single-photon detector 105 is incided after circulator output.
Wherein, the entrance port of pulse light and the incident circulator 104 of rear orientation light, and export the outgoing of circulator
Mouth is differed.
In this example, pulse light between laser 102, attenuator 103, circulator 104 and detection optical fiber, and
Rear orientation light is transmitted between detection optical fiber, circulator 104 and upper conversion single-photon detector 105 by polarization maintaining optical fibre.Protect
Polarisation fibre ensures pulse light and rear orientation light with TM00Pattern is transmitted.
The upper conversion single-photon detector 105 be used for by pump light and the rear orientation light carry out nonlinear optics and
Frequently, pair and frequency light carries out narrow-band filtering, will be after narrow-band filtering and frequency light be converted into TTL gate TTL telecommunications
Number output, the pump wavelength be 1900nm to 2000nm.
Optionally, pump light is exported by the single-mode laser of Advalue companies.The pump light λ1, back scattering
Light λ2, and frequency light λ3Between relation be：
Wherein, and frequency light λ3It is definite value in the system that waveguide is identical, temperature is fixed.
Described and frequency light λ3For the definite value of an experimental detection.For example, in practical application of the present invention, at 50 DEG C, and frequency
Light λ3For 864nm.When OTDR systematic parameters are fixed, and frequency light is definite value, and formula is met between pump light and rear orientation light
（1）.
Optionally, changed in the present invention wave-length coverage for the pump light that single-photon detector 105 is used into 1900nm extremely
2000nm, compared with prior art, employs the longer pump light of wavelength to realize nonlinear optics and frequency.Pump wavelength compared with
It is long, on the one hand, the noise that conversion light is brought under the Spontaneous Parametric of pump light can be avoided；On the other hand, pumping wavelength is shorter
When, Raman noise is Stokes photon；When pumping wavelength is longer, Raman noise is anti-Stokes photon.Under the same terms,
The cloth inning of anti-Stokes photon is fewer than Stokes photon, so reduces whole upper conversion single-photon detector 105
Noise, there is lower NEP values than other detectors.Because NEP values are lower, detectable dynamic range is bigger.Therefore, in phase
It is bigger than the dynamic range that other detectors are detected when same rear orientation light is incident.Equally, the dynamic model of identical is being obtained
When enclosing, upper conversion single-photon detector 105 can reduce the optical signal pulses width of rear orientation light input, that is, reduce pulse
The pulse width of flashlight, improves the resolution sizes of detection.
Optionally, it is upper conversion single-photon detector 105 include Volume Bragg grating, the Volume Bragg grating be used for pair
Narrow-band filtering is carried out with frequency light.
The minimum dimension of Volume Bragg grating is long 16mm, 3.5mm, and high 3.5mm cube, and frequency light are incided
The 3.5mm*3.5mm plane of incidence.In embodiment, the size of Volume Bragg grating can be used for long 16mm, 8mm, it is high
6mm.Volume Bragg grating is according to Bragg condition（2dsinθ=nλ）To select direction and the wavelength of Bragg diffraction.Body Bradley
Lattice grating has a very narrow wavelength bandwidth, wavelength bandwidth be 0.02nm between 0.1nm, in embodiment, ripple can be used
Length is with a width of 0.05nm.The reflected wavelength range of Volume Bragg grating is 830nm between 880nm.Pass through body Bradley with frequency light
Lattice grating is carried out after narrow-band filtering, is filtered out most of noise, NEP values is reached -140dbm/Hz ∧（1/2）.Namely
Say, upper conversion single-photon detector can detect -140dbm light in the present invention, under the same conditions, with using other
The upper sub- detector of converting unit is compared, measurement identical apart from when, just have higher resolution ratio.
Also, because upper conversion single-photon detector 105 is operated under free-run patterns, with traditional detector phase
Than reducing detection time.
With working in the indium GaAs under gate-control signal（InGaAs）Avalanche diode single-photon detector is compared, during detection
Between small three orders of magnitude, the time of detection is 10 minutes.
Also, compared with the OTDR of superconducting single-photon detector, without liquid nitrogen refrigerating, cost is low, small volume.
Optionally, the upper conversion single-photon detector 105 includes：Avalanche silicon diode.
Optionally, the time jitter jitter of the avalanche silicon diode is 500ps.
The degree of accuracy for the distance that one time of determination occurs is OTDR positioning precision, upper conversion single-photon detecting in OTDR
The positioning precision for surveying the OTDR of device depends on the time jitter of upper conversion single-photon detector, and time jitter is smaller, positioning precision
It is higher.Relation between time jitter t and positioning precision L is：
Wherein, c is the light velocity, and n is the refractive index of optical fiber.
In experiment, as n=1.5, time jitter is 500ps, then positioning precision is 10cm.
Avalanche silicon diode in upper conversion single-photon detector 105, does not have afterpulse phenomenon, effectively avoids Fei Nie
The blind area occurred after your reflection peak.
The upper conversion single-photon detector is used to pump light and the rear orientation light carrying out nonlinear optics and frequency,
TTL gate TTL electric signal outputs will be converted into frequency light；
The trigger 101 exports electric impulse signal to time-to-digit converter 106, the upper conversion single photon detection
Device 105 is by TTL electric signal outputs to time-to-digit converter 106.
Trigger 101 is exported to the electric impulse signal of time-to-digit converter 106 as beginning Start signals；Upper conversion
Single-photon detector 105 is exported to the TTL electric signals of time-to-digit converter 106 as end Stop signals.
The time-to-digit converter 106 is using on electric impulse signal detection optical fiber position different with TTL electric signal measurements
Corresponding photon counting.
As shown in the above, the method have the advantages that：
The invention provides a kind of fiber optical time domain reflection instrument, with using the classical light such as PMT, PIN and APD in the prior art
The OTDR of detector is different, and the OTDR in the present invention uses upper conversion single-photon detector, and upper conversion single-photon detector is used
1900nm to 2000nm pump wavelength, pair and frequency light carry out narrow-band filtering, obtained under identical quantum efficiency than classics spy
The lower NEP of device is surveyed, its NEP value can reach -140dbm, and because NEP value is lower, the dynamic range detected is bigger, on
Conversion single-photon detector effectively increases the dynamic range that OTDR can be measured, and improves the resolution ratio of detection；
Upper conversion single-photon detector uses free-run mode of operation, effectively reduces time of measuring；
With working in the indium GaAs under gate-control signal（InGaAs）Avalanche diode single-photon detector is compared, during detection
Between small three orders of magnitude；
Compared with the OTDR of superconducting single-photon detector, without liquid nitrogen refrigerating, cost is low, small volume；
Avalanche silicon diode is linear without afterpulse in upper conversion single-photon detector, effectively avoids Fresnel anti-
Penetrate the blind area occurred behind peak.
Embodiment two
Fig. 2 is a kind of structural representation of fiber optical time domain reflection instrument embodiment two of the invention, compared with embodiment one, the dress
Putting also includes Polarization Controller, and described device includes：
Trigger 101, laser 102, attenuator 103, circulator 104, upper conversion single-photon detector 105, time number
Word converter 106 and Polarization Controller 201.
Wherein, optical signal is between laser 102, attenuator 103, circulator 104 and upper conversion single-photon detector 106
Transmitted by single-mode fiber.
Pulse light is between laser 102, attenuator 103, circulator 104 and detection optical fiber, and back scattering
Light detection optical fiber, circulator 104, Polarization Controller 201, on conversion single-photon detector 105 between passed by single-mode fiber
It is defeated.
The electric impulse signal triggering laser 102 that the trigger 101 is exported produces the pulse light of identical frequency, institute
State pulse light and incide the circulator 104 after the attenuator 103 decay, exported from the circulator 104
Pulse light incides detection optical fiber, and pulse light obtains back scattering light output extremely after detection optical fiber Rayleigh scattering
Circulator 104, the rear orientation light incides Polarization Controller 201, the Polarization Controller after the output of circulator 104
Rear orientation light is adjusted to TM by 20100The supreme conversion single-photon detector 105 of polarization light output of pattern；
The upper conversion single-photon detector 105 be used for by pump light and the rear orientation light carry out nonlinear optics and
Frequently, the Volume Bragg grating pair and frequency light in upper conversion single-photon detector 105 carry out narrow-band filtering, by the sum after narrow-band filtering
Frequency light is converted into TTL gate TTL electric signal outputs；
The trigger 101 exports electric impulse signal to time-to-digit converter 106, the upper conversion single photon detection
Device 105 is by TTL electric signal outputs to time-to-digit converter 106；
The time-to-digit converter 106 is using on electric impulse signal detection optical fiber position different with TTL electric signal measurements
Corresponding photon counting.
The description such as parameter of equipment and the type of embodiment one, are no longer repeated one by one here in fiber optical time domain reflection instrument.
With reference to specific fiber-optic probe experimental result, to the beneficial effect of fiber optical time domain reflection instrument provided by the present invention
Fruit is described further.Employed in experiment for the fiber optical time domain reflection instrument described in embodiment two, optical signal is in each portion
Transmitted between part by single-mode fiber.
Experiment one, experiment two and experiment four are the single-mode fiber spatial discriminations that different length is detected to fiber optical time domain reflection instrument
The analysis of rate experimental result；Experiment three is the result that the dynamic range that 170km optical fiber is detected is detected to fiber optical time domain reflection instrument
Analysis.
Experiment one
Experimental setup parameters：12.5km single-mode fiber is detected, the frequency of electric impulse signal is 8kHz, and pulse width is
500ps, sets an extruding point as the pip of pulse light, detection time 3 at distance measurement optical fiber connector 15cm
Minute（Detection time can also be 10 minutes）, obtain Fig. 3 measurement result.
Wherein, the relation in the frequency f and optical fiber of electric impulse signal between light velocity v, detection optical fiber length L meets formula
（3）：
Analysis of experimental results：From the measurement result in Fig. 3, there are two Hes of reflection peak 301 in data result front end
302, this be due to circulator 104 isolation have certain error caused by.Between reflection peak 301 and reflection peak 302
Distance is 1m, is coincide with the distance of photo-signal channel in the circulator 104 of actual measurement.
There are two reflection peaks 303 and 304 in the rear end of Fig. 3 measurement data results, the two reflection peaks are by distance measurement
The primary event of pip pulse signals light at optical fiber connector 15cm, and detection optical fiber end pulse signals light are another
What outer primary event was formed.As the above analysis, fiber optical time domain reflection instrument provided by the present invention detects 12.5km single mode
Optical fiber, spatial resolution can at least reach 15cm.
Experiment two
Experimental setup parameters：86km single-mode fiber is detected, according to formula（2）The frequency for obtaining electric impulse signal is 1kHz,
Pulse width is 10ns, and the FC-FC single-mode fiber jumpers that a length is 2m, detection time 3 are accessed in detection optical fiber end
Minute, obtain Fig. 4 measurement result.
Analysis of experimental results：As shown in Figure 4, there are two reflection peaks 401 and 402 in experimental data rear end, the two reflections
Peak is to be believed by the primary event of detection optical fiber end pulse signals light, and 2m FC-FC single-mode fiber jumpers for pulse
What the primary event of number light was formed.The distance between reflection peak 401 and reflection peak 402 are 2m in Fig. 4, are kissed with actual measured results
Close.As the above analysis, fiber optical time domain reflection instrument provided by the present invention detects 86km single-mode fiber, and spatial resolution is extremely
2m can be reached less.
Experiment three
Experimental setup parameters：170km single-mode fiber is detected, according to formula（2）The frequency of electric impulse signal is
500Hz, pulse width is 10 μ s, pulse light input attenuator 103 is decayed so that reflected from detection optical fiber
Rear orientation light by it is upper conversion 105 count pick up of single-photon detector when, close to saturation count, detection time 3 minutes is obtained
To Fig. 5 measurement result.
As seen from Figure 5, upper conversion single-photon detector is caused to be in off position at 0-20km, for avoiding
Damaged due to reasons such as misoperations and change single-photon detector.Data result is shown, upper to change single-photon detector institute energy
The dynamic range of detection can reach 45dbm,（22.5dbm*2=45dbm in figure）, about 125km.
Experiment four
Experimental setup parameters：216km single-mode fiber is detected, the frequency of electric impulse signal is 400Hz, and pulse width is 10
μ s, 216km detection optical fiber are made up of two sections of 108km optical fiber, detection time 3 minutes, obtain Fig. 6 measurement result.Fig. 6
（1）- Fig. 6（5）Middle abscissa represents bin number.
Because 216km detection optical fiber is long, it is divided into two sections of optical fiber and is detected.Upper conversion single-photon detector is not added with
During gate-control signal, detection be 0 to 120km detection optical fiber, regulated attenuator cause change single-photon detector counting
During for 44W, measure 3 minutes, obtain Fig. 6（1）Measurement result.
When upper conversion single-photon detector adds gate-control signal（Dutycycle is 60%）, detection be 100 to 216km detection
Optical fiber, regulation gate signal delay so that above change single-photon detector and count minimum, regulated attenuator is gradually decrease to undamped
When, upper conversion single-photon detector is counted as 67W, measures 3 minutes, obtains Fig. 6（2）Data result, Fig. 6（2）Back end reflective
Such as Fig. 6 after peak 602 amplifies（3）It is shown.
5m FC-FC single-mode fiber jumpers are added in 216km detection optical fiber end.Upper conversion single-photon detector adds door
When controlling signal（Dutycycle is 60%）, detection be 100 to 221km detection optical fiber, regulation gate signal delay so that upper conversion
Single-photon detector counts minimum, and when regulated attenuator is gradually decrease to undamped, upper conversion single-photon detector is counted as
60W, measures 3 minutes, obtains Fig. 6（4）Data result, Fig. 6（4）Such as Fig. 6 after back end reflective peak 603 amplifies（5）It is shown.
By Fig. 6（1）0 to 120km optical fiber detection data result and Fig. 6（2）100 to 216km optical fiber detection data knot
Fruit is combined, and is node with front end reflection peak 601, obtains Fig. 6（6）The result of detection of shown whole 216 detection optical fiber
（It is clear in order to show, Fig. 6（6）To amplify the result schematic diagram after 5 times）.Fig. 6（7）For Fig. 6（6）Back end reflective peak 602 is put
Big figure, it can be seen that the position of back end reflective peak 602 is 214302m.
Will figure（1）0 to 120km optical fiber detection data result and Fig. 6（4）100 to 221km optical fiber detection data result
Combine, be node with front end reflection peak 601, obtain Fig. 6（8）The result of detection of shown whole 221 detection optical fiber（For
Display is clear, Fig. 6（8）To amplify the result schematic diagram after 5 times）.Fig. 6（9）For Fig. 6（8）The amplification at back end reflective peak 603
Figure, it can be seen that the position of back end reflective peak 603 is 214307m.
It can be seen from result of detection, when detecting 216km optical fiber, 1m resolution ratio can be reached.
Fig. 6（3）And Fig. 6（5）Back end reflective peak differs 444-439=5 bin（When not having specified otherwise, 1 bin is
512ps*20=10.24ns）, it is apart from S-phase difference
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all essences in the present invention
God is with principle, and any modification, equivalent substitution and improvements made etc. should be included in the scope of the protection.
Claims (9)
1. a kind of fiber optical time domain reflection instrument, it is characterised in that the fiber optical time domain reflection instrument includes：
Trigger, laser, attenuator, circulator, upper conversion single-photon detector and time-to-digit converter；
The trigger is used for the electric impulse signal for exporting predeterminated frequency；
The electric impulse signal triggering laser of the trigger output produces the pulse light of identical frequency, the pulse signal
Light incides the circulator after attenuator decay, and the pulse light exported from the circulator incides detection
Optical fiber, pulse light obtains back scattering light output to circulator after detection optical fiber Rayleigh scattering, the back scattering
Light incides upper conversion single-photon detector after circulator is exported, and the circulator is a multiport device, the biography of light
Defeated to be gone in ring along one direction, opposite direction is isolation；
The upper conversion single-photon detector is used to pump light and the rear orientation light carrying out nonlinear optics and frequency, pair and
Frequency light carries out narrow-band filtering, and after narrow-band filtering and frequency light is converted into TTL gate TTL electric signal outputs,
The pump wavelength be 1900nm to 2000nm, described and frequency light is 864nm；
The trigger exports electric impulse signal to time-to-digit converter, and the upper conversion single-photon detector is electric by TTL
Signal output is to time-to-digit converter；
The time-to-digit converter utilizes corresponding light on electric impulse signal detection optical fiber position different with TTL electric signal measurements
Sub-count；
Wherein, optical signal is passed between laser, attenuator, circulator and upper conversion single-photon detector by polarization maintaining optical fibre
It is defeated.
2. fiber optical time domain reflection instrument according to claim 1, it is characterised in that the upper conversion single-photon detector bag
Include：
Volume Bragg grating, the Volume Bragg grating be used for pair and frequency light carry out narrow-band filtering.
3. fiber optical time domain reflection instrument according to claim 2, it is characterised in that
The size of the Volume Bragg grating is more than or equal to 3.5mm*3.5mm*16mm cube.
4. fiber optical time domain reflection instrument according to claim 1, it is characterised in that the trigger includes：
Microwave signal generator and encoder；
The microwave signal generator is used to export inceptive impulse signal；
The encoder is used to encode the inceptive impulse signal, exports the electric impulse signal of predeterminated frequency.
5. fiber optical time domain reflection instrument according to claim 4, it is characterised in that it is first that the microwave signal generator is exported
The frequency of initial pulse signal includes：
10GHz。
6. fiber optical time domain reflection instrument according to claim 1, it is characterised in that
The laser output power is 1W, and wavelength is 150.12nm, and pulse width is that 50ps is tunable to 10 μ s.
7. fiber optical time domain reflection instrument according to claim 1, it is characterised in that the upper conversion single-photon detector bag
Include：
Avalanche silicon diode.
8. fiber optical time domain reflection instrument according to claim 7, it is characterised in that
The time jitter of the avalanche silicon diode is 500ps.
9. the fiber optical time domain reflection instrument according to claim 1-8 any one, it is characterised in that
Optical signal is transmitted between laser, attenuator, circulator and upper conversion single-photon detector by single-mode fiber；
Then the fiber optical time domain reflection instrument also includes：
Polarization Controller, for pump light and the rear orientation light to be adjusted into TM00The polarised light of pattern.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310380182.5A CN104426602B (en) | 2013-08-27 | 2013-08-27 | A kind of fiber optical time domain reflection instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310380182.5A CN104426602B (en) | 2013-08-27 | 2013-08-27 | A kind of fiber optical time domain reflection instrument |
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| Publication Number | Publication Date |
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| CN102243107A (en) * | 2011-04-20 | 2011-11-16 | 张强 | High-sensitivity up-conversion single photon detection system |
| CN102506904A (en) * | 2011-10-17 | 2012-06-20 | 南京大学 | Spontaneous Brillouin scattering optical time domain reflectometer based on superconductive nanowire single-proton detector |
| CN103051377A (en) * | 2012-12-26 | 2013-04-17 | 桂林聚联科技有限公司 | Method for precisely positioning fault of optical cable by utilizing rayleigh scattering and coherent optical time domain reflection technology |
| CN203504566U (en) * | 2013-08-27 | 2014-03-26 | 张强 | Optical time-domain reflectometer |
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| CN102243107A (en) * | 2011-04-20 | 2011-11-16 | 张强 | High-sensitivity up-conversion single photon detection system |
| CN102506904A (en) * | 2011-10-17 | 2012-06-20 | 南京大学 | Spontaneous Brillouin scattering optical time domain reflectometer based on superconductive nanowire single-proton detector |
| CN103051377A (en) * | 2012-12-26 | 2013-04-17 | 桂林聚联科技有限公司 | Method for precisely positioning fault of optical cable by utilizing rayleigh scattering and coherent optical time domain reflection technology |
| CN203504566U (en) * | 2013-08-27 | 2014-03-26 | 张强 | Optical time-domain reflectometer |
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