CN206056611U - Phase sensitive OTDR phase demodulating systems - Google Patents
Phase sensitive OTDR phase demodulating systems Download PDFInfo
- Publication number
- CN206056611U CN206056611U CN201620769480.2U CN201620769480U CN206056611U CN 206056611 U CN206056611 U CN 206056611U CN 201620769480 U CN201620769480 U CN 201620769480U CN 206056611 U CN206056611 U CN 206056611U
- Authority
- CN
- China
- Prior art keywords
- signal
- electrically connected
- phase
- detector
- pass filter
- 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.)
- Active
Links
Landscapes
- Optical Communication System (AREA)
Abstract
This utility model provides a kind of phase sensitive OTDR phase demodulating systems, and the system includes cross-correlation circuit, and cross-correlation circuit is electrically connected with balance photo-detector；Cross-correlation circuit includes process circuit, frequency mixer and the first low pass filter, and process circuit is electrically connected with balance photo-detector and frequency mixer respectively, and frequency mixer sends mixed frequency signal to the first low pass filter；Process circuit includes the first process path and second processing path, balance photo-detector processes path to first and sends first signal of telecommunication, balance photo-detector sends second signal of telecommunication to second processing path, and the first process path and second processing path are electrically connected with two inputs of frequency mixer respectively.The system can remove laser phase noise, simplify signal demodulating circuit, need not solve the problems, such as optical signal with the signal of telecommunication with frequency.
Description
Technical field
This utility model is related to phase sensitive optical time domain reflectometer field, specifically, is related to a kind of phase based on cross-correlation
Position sensitivity OTDR phase demodulating systems.
Background technology
Optical time domain reflectometer (Optical Time Domain Reflectometry, be abbreviated as OTDR) is for external world
Vibrational perturbation event is monitored, it is possible to achieve vibrational perturbation event location is accurately positioned to external world, with the distribution of line shape formula
The advantages of measurement, long-range measurement, high sensitivity, strong anti-electromagnetic interference capability, good insulating, essential safety, little lightweight,
Using widely.
After on market, phase sensitive OTDR is interfered with return Rayleigh scattering light using intrinsic light, then sent out by signal
Raw device is produced two-way orthogonal signalling homogenous frequency signal and is mixed with return interference light signal, after low-pass filtering is just producing two-way
Hand over signal.This two-way orthogonal signalling can solve the return light phase value of optical fiber each several part by orthogonal signalling process.But this phase place
Demodulation method circuit is complicated, must carry out laser phase noise and filter after signal is return, while needing to solve acousto-optic modulation signal
The problem with frequency is required with orthogonal signalling.
The content of the invention
The purpose of this utility model is to provide a kind of removal laser phase noise, simplifies signal demodulating circuit, without the need for solution
The certainly phase sensitive OTDR phase demodulating systems of optical signal and the signal of telecommunication with frequency problem.
To achieve these goals, the phase sensitive OTDR phase demodulating systems that this utility model is provided include that narrow linewidth swashs
Light device, the first bonder, modulated amplifier part, circulator, the second bonder and balance photo-detector, narrow linewidth laser to
First bonder send the first optical signal, the first bonder to modulated amplifier part send the second optical signal, the first bonder to
Second bonder sends the 3rd optical signal, and modulated amplifier part is transported to being visited of being connected with circulator by modulated optical signal is amplified
In light-metering fibre, it is detected optical fiber and Rayleigh optical signal, two outputs of the second bonder is conveyed to the second bonder by circulator
End is connected with balance photo-detector.Phase demodulating system also includes cross-correlation circuit, cross-correlation circuit and balance photo-detector electricity
Connection；Cross-correlation circuit includes process circuit, frequency mixer and the first low pass filter, process circuit respectively with balance optical detection
Device and frequency mixer electrical connection, frequency mixer send mixed frequency signal to the first low pass filter；Process circuit includes the first process path
With second processing path, to first process path first signal of telecommunication of transmission, balance photo-detector is at second for balance photo-detector
Reason path sends second signal of telecommunication, and the first process path and second processing path are electrically connected with two inputs of frequency mixer respectively
Connect.
From such scheme, phase sensitive OTDR phase demodulatings system of the present utility model is powered-down mutually by increasing
Road so that optical signal and the same frequency of the signal of telecommunication, so as to solve the problems, such as to need optical signal with the signal of telecommunication with frequency.
In one scheme, the first process path includes the first depositor, delay circuit, the first normalization module and the first mistake
Zero detection module, the first depositor with balance photo-detector electrically connect, delay circuit respectively with the first depositor and the first normalizing
Change module electrical connection, the first zero passage detection module electrically connected with the first normalization module, the first zero passage detection module and frequency mixer
Electrical connection.Second processing path includes the second depositor, the second normalization module and the second zero passage detection module, the second depositor
Electrically connect with balance photo-detector, the second normalization module is electrically connected with the second depositor and the second zero passage detection module respectively,
Second zero passage detection module is electrically connected with frequency mixer.
As can be seen here, by the first process path and the light letter for returning detected optical fiber respectively of second processing path
Number processed, wherein, the optical signal of return is carried out delay a cycle by the first process path so that first processes path light
The phase place of signal is identical with the phase place of the optical signal of second processing path.
In further scheme, the first normalization module includes the first doubler and the second low pass filter, the first frequency multiplication
Device is electrically connected with delay circuit and the second low pass filter respectively, and the second low pass filter is electrically connected with the first zero passage detection module
Connect.Second normalization module includes the second doubler and the 3rd low pass filter, the second doubler respectively with the second depositor and
3rd low pass filter is electrically connected, and the 3rd low pass filter is electrically connected with the second zero passage detection module.
From such scheme, the first normalization module and the second normalization module are respectively provided with by doubler and low-pass filtering
Device, can obtain the amplitude of every segment signal in detected optical fiber, and make the amplitude of every segment signal consistent, be easy to data processing.
In further scheme, phase demodulating system also includes capture card, and capture card is electrically connected with the first low pass filter.
As can be seen here, the signal data after capture card acquisition process is set, the data analysiss of next step are convenient for.
In further scheme, modulated amplifier part includes acousto-optic modulator and erbium-doped fiber amplifier, acousto-optic modulator
Receiving the second optical signal and modulated optical signal being exported to erbium-doped fiber amplifier, erbium-doped fiber amplifier sends to circulator and amplifies
Modulated optical signal.
It follows that acousto-optic modulator can allow laser pulse to obtain the shift frequency of fixed frequency.Erbium-doped fiber amplifier can be put
Big laser pulse, be lifted in detected optical fiber return light signal strength.
Description of the drawings
Fig. 1 is the system block diagram of this utility model phase sensitive OTDR phase demodulating systems.
Fig. 2 is the structured flowchart of cross-correlation circuit in this utility model phase sensitive OTDR phase demodulating systems.
Fig. 3 is the sinusoidal wave form schematic diagram of first signal of telecommunication in this utility model phase sensitive OTDR phase demodulating systems.
Fig. 4 is that first signal of telecommunication is converted into the waveform after square wave in this utility model phase sensitive OTDR phase demodulating systems
Schematic diagram.
Fig. 5 is the sinusoidal wave form schematic diagram of second signal of telecommunication in this utility model phase sensitive OTDR phase demodulating systems.
Fig. 6 is that second signal of telecommunication is converted into the waveform after square wave in this utility model phase sensitive OTDR phase demodulating systems
Schematic diagram.
Fig. 7 is waveform of the mixed frequency signal at Δ α (i)=0 ° in this utility model phase sensitive OTDR phase demodulating systems
Schematic diagram.
Fig. 8 be in this utility model phase sensitive OTDR phase demodulating systems mixed frequency signal Δ α (i) for 0 ° and 90 ° it
Between when waveform diagram.
Fig. 9 is ripple of the mixed frequency signal at Δ α (i)=180 ° in this utility model phase sensitive OTDR phase demodulating systems
Shape schematic diagram.
Below in conjunction with drawings and Examples, the utility model is described in further detail.
Specific embodiment
As shown in figure 1, phase sensitive OTDR phase demodulating systems of the present utility model include narrow linewidth laser 1, first
Bonder 2, modulated amplifier part 20, circulator 5, the second bonder 6, balance photo-detector 7, cross-correlation circuit 8 and collection
Card 9, narrow linewidth laser 1 send the first optical signal to the first bonder 2, and the first bonder 2 is sent to modulated amplifier part 20
Second optical signal, the first bonder 2 send the 3rd optical signal to the second bonder 6, and modulated amplifier part 20 will amplify modulation light
Signal is transported in the detected optical fiber 10 being connected with circulator 5.Wherein, modulated amplifier part 20 includes 3 He of acousto-optic modulator
Erbium-doped fiber amplifier 4, acousto-optic modulator 3 receive the second optical signal and export modulated optical signal to erbium-doped fiber amplifier 4, mix
Doped fiber amplifier 4 sends to circulator 5 and amplifies modulated optical signal.Detected optical fiber 10 is by circulator 5 to the second bonder 6
Conveying Rayleigh optical signal, two outfans of the second bonder 6 are connected with balance photo-detector 7.Cross-correlation circuit 8 and balance light
Detector 7 is electrically connected.
Referring to Fig. 2, cross-correlation circuit 8 includes process circuit, frequency mixer 17 and the first low pass filter 19, process circuit
Electrically connect with balance photo-detector 7 and frequency mixer 17 respectively, frequency mixer 17 sends mixed frequency signal to the first low pass filter 19.Place
Reason circuit includes the first process path 81 and second processing path 82, and balance photo-detector 7 processes path 81 to first and sends the
One signal of telecommunication, balance photo-detector 7 send second signal of telecommunication to second processing path 82, and first processes path 81 and second processing
Path 82 is electrically connected with two inputs of frequency mixer 17 respectively.Capture card 9 is electrically connected with the first low pass filter 19.
Wherein, the first process path 81 includes the first depositor 11, delay circuit 14, the first normalization module 16 and first
Zero passage detection module 18, the first depositor 11 with balance photo-detector 7 electrically connect, delay circuit 14 respectively with the first depositor 11
Electrically connect with the first normalization module 16, the first zero passage detection module 18 is electrically connected with the first normalization module 16, the first zero passage
Detection module 18 is electrically connected with frequency mixer 16.First normalization module 16 includes the first doubler 161 and the second low pass filter
162, the first doubler 161 is electrically connected with delay circuit 14 and the second low pass filter 162 respectively, the second low pass filter 162
Electrically connect with the first zero passage detection module 18.Second processing path 82 includes the second depositor 12,13 and of the second normalization module
Second zero passage detection module 15, the second depositor 12 are electrically connected with balance photo-detector 7, and the second normalization module 13 is respectively with the
Two depositors 12 and the second zero passage detection module 15 are electrically connected, and the second zero passage detection module 15 is electrically connected with frequency mixer 17.Second
Normalization module 13 includes the second doubler 131 and the 3rd low pass filter 132, and the second doubler 131 is deposited with second respectively
Device 12 and the 3rd low pass filter 132 are electrically connected, and the 3rd low pass filter 132 is electrically connected with the second zero passage detection module 15.
Narrow linewidth laser 1 produces coherence length laser signal, when optical signal is divided into two-way through the first bonder 2, its
In all the way optical signal enter modulated amplifier part 20 acousto-optic modulator 3 in, acousto-optic modulator 3 by the optical signal modulation be shift frequency
Light pulse and send it to erbium-doped fiber amplifier 4 and carry out luminous power amplification, the signal after luminous power is amplified passes through
Optical fiber circulator 5 is input in detected optical fiber 10 and transmits, optical signal transmit in detected optical fiber 10 will excite it is return auspicious
Sharp optical signal, return Rayleigh optical signal are dorsad transferred to up in circulator 5 along detected optical fiber 10.First bonder 2
The Rayleigh optical signal that another road optical signal for separating is obtained with circulator 5 is injected separately into two inputs of the second bonder 6
Mouthful, two ways of optical signals passes coherent transfer in the second bonder 6 and obtains the intersecting sinusoidal signal of two-way.The intersecting sine of two-way
Signal carries out light through two output ports of the second bonder 6 in balance photo-detector 7 and in balance photo-detector 7
Electricity conversion, meanwhile, two paths of signals subtracts each other the beat frequency signal of telecommunication for obtaining Rayleigh optical signal.The beat frequency signal of telecommunication for obtaining is transported to mutually
Interlock circuit 8 carries out cross correlation process.
In cross-correlation circuit 8, beat signal is respectively enterd and is separately stored in the first deposit according to the difference in sampling time
In device 11 and the second depositor 12, the signal in the first depositor 11 and the second depositor 12 differs a time cycle.If the
First signal of telecommunication in one depositor 11 is：First
Electric signal waveform figure referring to Fig. 3, second signal of telecommunication in the second depositor 12 is：
Wherein, f0For acousto-optic
The shift frequency frequency of manipulator 3, i are sampling ordinal number, and t is the return Reyleith scanttering light signal time of detected optical fiber 10, and A is amplitude, α
The phase pushing figure of beat signal during to sample every time,The phase place of per section of 10 beat signal of detected optical fiber during to sample every time
Value, the second electric signal waveform figure are as shown in Figure 5.
The signal amplitude value obtained due to sampling every time is different, for the ease of comparing, the signal of telecommunication need to be normalized place
The amplitude of signal is adjusted to same-amplitude by reason.As first signal of telecommunication and second signal of telecommunication differ a time cycle, it is
The phase time for eliminating first signal of telecommunication and second signal of telecommunication is poor, and first signal of telecommunication need to first pass through delay circuit 14, delay one
The individual time cycle, it is resent to the first normalization module 14.In the first normalization module 14, first signal of telecommunication is through first times
The frequency multiplication of frequency device 161 obtains the amplitude of the first signal：
Through the filter of the second low pass filter 162
Amplitude is obtained after ripple：A1 (i, t)=A (t)2。
First signal of telecommunication is normalized and obtains：
First signal of telecommunication is transferred to the first zero passage detection module 18 side of being converted into after being processed by the first normalization module 14
Ripple signal：
Wherein, u is one
Preset constant, N are frequency cycle.It is as shown in Figure 4 that first signal of telecommunication is converted into the oscillogram after square wave.
Second normalization module 13 receives second signal of telecommunication from the second depositor 12, and second signal of telecommunication is through the second frequency multiplication
The frequency multiplication of device 131 obtains the amplitude of secondary signal：
Through the 3rd low pass filter 132
Filtering after obtain amplitude：A1 (i+1, t)=A (t)2。
Second signal of telecommunication is normalized and obtains：
Second signal of telecommunication is transferred to the first zero passage detection module 15 side of being converted into after being processed by the second normalization module 13
Ripple signal：
It is as shown in Figure 6 that second signal of telecommunication is converted into the oscillogram after square wave.
The square-wave signal of first signal of telecommunication conversion and the square-wave signal of second signal of telecommunication conversion are transferred in frequency mixer 17
Carry out multiplicative mixing, obtain mixed frequency signal Z (i, t)=y (i, t) × y (i+1, t).Signal Z (i, t) is further transmitted to
Low-pass filtering, and 9 gathered statistics of collected card are carried out in one low pass filter 19.According to the mixed frequency signal Z gathered by capture card
(i, t), obtains using the formula between frequency shift signal and phase signal：
Wherein, frequency shift signal is：△ α (i)=α (i+1)-α (i), therefore can draw, phase signal is：Due in the signal of every single acquisition, △ α (i)
It is fixed value, by exchanging item output, you can demodulate the phase contrast between 10 each sections of return signals of detected optical fiber, according to phase place
Poor difference can extrapolate each section of return signal.
Referring to Fig. 7, when △ α (i)=0 °, value of mixed frequency signal Z (i, t) within the time cycle is maximum u2, now,
The dutycycle (as shown in hatched area) of mixed frequency signal Z (i, t) is maximum 1.Referring to Fig. 8, when △ α (i) is at 0 ° and 90 °
Between when, value of mixed frequency signal Z (i, t) within the time cycle be located at 0 to u2Between, now, the duty of mixed frequency signal Z (i, t)
Than between 0.5 to 1.When △ α (i)=90 °, value of mixed frequency signal Z (i, t) within the time cycle is 0, now, mixing letter
The dutycycle of number Z (i, t) is 0.5.When △ α (i) is between 90 ° and 180 °, mixed frequency signal Z (i, t) is within the time cycle
Value is located at 0 to-u2Between, now, the dutycycle of mixed frequency signal Z (i, t) is between 0 to 0.5.Referring to Fig. 9, when △ α (i)=
When 180 °, value of mixed frequency signal Z (i, t) within the time cycle is minima-u2, therefore, the dutycycle of mixed frequency signal Z (i, t)
For minima 0.
From the foregoing, phase sensitive OTDR phase demodulatings system of the present utility model is by increasing cross-correlation circuit, can
Remove the phase noise brought by laser instrument so that optical signal is with the signal of telecommunication with frequency.Meanwhile, simplify signal demodulating circuit.
It should be noted that preferred embodiment of the present utility model is these are only, but the design concept of utility model is not
This is confined to, all insubstantial modifications made to this utility model using this design also each fall within protection of the present utility model
Within the scope of.
Claims (7)
1. phase sensitive OTDR phase demodulatings system, including narrow linewidth laser, the first bonder, modulated amplifier part, annular
Device, the second bonder and balance photo-detector, the narrow linewidth laser send the first optical signal to first bonder,
First bonder sends the second optical signal to the modulated amplifier part, and first bonder is to second bonder
Send the 3rd optical signal, the modulated amplifier part will amplify modulated optical signal and be transported to being detected of be connected with the circulator
In optical fiber, the detected optical fiber conveys Rayleigh optical signal, second coupling to second bonder by the circulator
Two outfans of clutch are connected with the balance photo-detector, it is characterised in that：
The phase demodulating system also includes cross-correlation circuit, and the cross-correlation circuit is electrically connected with the balance photo-detector；
The cross-correlation circuit includes process circuit, frequency mixer and the first low pass filter, the process circuit respectively with institute
Balance photo-detector and frequency mixer electrical connection are stated, the frequency mixer sends mixed frequency signal to first low pass filter；
The process circuit includes the first process path and second processing path, and the balance photo-detector is processed to described first
Path send first signal of telecommunication, the balance photo-detector to the second processing path send second signal of telecommunication, described first
Process path and the second processing path is electrically connected with two inputs of the frequency mixer respectively.
2. phase sensitive OTDR phase demodulating systems according to claim 1, it is characterised in that：Described first processes path
Including the first depositor, delay circuit, the first normalization module and the first zero passage detection module, first depositor with it is described
Balance photo-detector electrical connection, the delay circuit are electrically connected with first depositor and the first normalization module respectively
Connect, the first zero passage detection module is electrically connected with the first normalization module, the first zero passage detection module with it is described
Frequency mixer is electrically connected.
3. phase sensitive OTDR phase demodulating systems according to claim 2, it is characterised in that：The second processing path
Including the second depositor, the second normalization module and the second zero passage detection module, second depositor is visited with the balance light
Device electrical connection is surveyed, the second normalization module is electrically connected with second depositor and the second zero passage detection module respectively
Connect, the second zero passage detection module is electrically connected with the frequency mixer.
4. phase sensitive OTDR phase demodulating systems according to claim 3, it is characterised in that：First normalized mode
Block includes the first doubler and the second low pass filter, first doubler respectively with the delay circuit and described second low
Bandpass filter is electrically connected, and second low pass filter is electrically connected with the first zero passage detection module.
5. phase sensitive OTDR phase demodulating systems according to claim 4, it is characterised in that：Second normalized mode
Block includes the second doubler and the 3rd low pass filter, second doubler respectively with second depositor and the described 3rd
Low pass filter is electrically connected, and the 3rd low pass filter is electrically connected with the second zero passage detection module.
6. phase sensitive OTDR phase demodulating systems according to any one of claim 1 to 5, it is characterised in that：The phase
Position demodulating system also includes capture card, and the capture card is electrically connected with first low pass filter.
7. phase sensitive OTDR phase demodulating systems according to any one of claim 1 to 5, it is characterised in that：The tune
Amplifying device processed includes acousto-optic modulator and erbium-doped fiber amplifier, the acousto-optic modulator receive second optical signal and to
The erbium-doped fiber amplifier exports modulated optical signal, and the erbium-doped fiber amplifier sends described amplification to the circulator and adjusts
Optical signal processed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620769480.2U CN206056611U (en) | 2016-07-19 | 2016-07-19 | Phase sensitive OTDR phase demodulating systems |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620769480.2U CN206056611U (en) | 2016-07-19 | 2016-07-19 | Phase sensitive OTDR phase demodulating systems |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206056611U true CN206056611U (en) | 2017-03-29 |
Family
ID=58376797
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620769480.2U Active CN206056611U (en) | 2016-07-19 | 2016-07-19 | Phase sensitive OTDR phase demodulating systems |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN206056611U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111678583A (en) * | 2020-06-17 | 2020-09-18 | 珠海任驰光电科技有限公司 | Optical fiber vibration measuring device and method for improving light source noise |
| CN113091782A (en) * | 2021-04-26 | 2021-07-09 | 太原理工大学 | PGC-based phase-sensitive optical time domain reflection system and phase demodulation method |
-
2016
- 2016-07-19 CN CN201620769480.2U patent/CN206056611U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111678583A (en) * | 2020-06-17 | 2020-09-18 | 珠海任驰光电科技有限公司 | Optical fiber vibration measuring device and method for improving light source noise |
| CN111678583B (en) * | 2020-06-17 | 2022-02-18 | 珠海任驰光电科技有限公司 | Optical fiber vibration measuring device and method for improving light source noise |
| CN113091782A (en) * | 2021-04-26 | 2021-07-09 | 太原理工大学 | PGC-based phase-sensitive optical time domain reflection system and phase demodulation method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105490738B (en) | Probe beam deflation method and system based on frequency synthesis | |
| CN107835055B (en) | Microwave source phase noise measurement method and system | |
| CN107063431A (en) | A kind of optical fiber vibration sensing system and method based on double light path | |
| CN105222816B (en) | Multi-parameter distributed optical fiber sensing system based on modulation pulse and multiple scattering | |
| CN102809430B (en) | Device for Brillouin optical time domain reflectometer based on optical phase-locked ring | |
| CN103674084A (en) | Method for simultaneously measuring distributed type temperatures and strain | |
| CN105067103A (en) | Vibration detection device and method based on optical frequency domain reflectometer | |
| CN107990970A (en) | The method for eliminating the noise that declines in distribution type fiber-optic acoustic systems | |
| CN108180853A (en) | A kind of Brillouin light Time Domain Reflectometry strain-Sensing device based on chaotic modulation | |
| CN113315573B (en) | Optical-assisted broadband microwave instantaneous frequency measurement method | |
| CN105136175A (en) | Phase-sensitive optical time domain reflection system based on self-mixing technology | |
| CN206056611U (en) | Phase sensitive OTDR phase demodulating systems | |
| CN110487308A (en) | A kind of high-performance coherent detection type Φ-OTDR realization system and method based on PGC demodulation | |
| CN102741563A (en) | Method and device for determining the position of a piston of a piston cylinder using microwaves | |
| CN102208942A (en) | Method of optical cable range finding with optical cable tracker, and optical cable tracker | |
| CN103604450A (en) | Seed injection BOTDR distributed optical fiber sensing system | |
| CN107436201A (en) | Distributed fiber optic temperature strain sensing system and method based on Brillouin scattering | |
| CN111780859A (en) | Distributed optical fiber sensing detection system | |
| CN105203136A (en) | Distributed sensing system based on differential amplification technology | |
| CN112833929A (en) | Disturbance monitoring system of heterodyne phi-OTDR technology based on local optical frequency shift | |
| CN205120239U (en) | Vibration detection device based on optical frequency domain reflectometer | |
| CN105910728B (en) | High spatial resolution Raman temperature transducer and temp measuring method | |
| CN104132677A (en) | Heterodyne interference type optical fiber sensing time division multiplexing system | |
| JP2004282693A5 (en) | ||
| CN104614091A (en) | All-fiber long-distance high-spatial-resolution single-photon temperature sensor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |