CN101377441A - Optical fiber temperature sensor based on wave length demodulation - Google Patents
Optical fiber temperature sensor based on wave length demodulation Download PDFInfo
- Publication number
- CN101377441A CN101377441A CNA2008102228750A CN200810222875A CN101377441A CN 101377441 A CN101377441 A CN 101377441A CN A2008102228750 A CNA2008102228750 A CN A2008102228750A CN 200810222875 A CN200810222875 A CN 200810222875A CN 101377441 A CN101377441 A CN 101377441A
- Authority
- CN
- China
- Prior art keywords
- temperature
- signal processor
- fiber
- wavelength
- temperature sensor
- 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.)
- Granted
Links
Images
Abstract
The invention discloses an optical fiber temperature sensor based on wave length demodulation, comprising a broadband light source, a fiber optic coupler, a polarizer, a polarization maintaining fiber ring, a temperature sensing head, an F-P tunable filter, a photo detector, an analog to digital converter and a signal processor. The tail fiber of the broadband light source is welded with the A end of the fiber optic coupler. The B end of the fiber optic coupler is welded with the fiber intake of the polarizer. The C end of the fiber optic coupler is welded with the E end of the F-P tunable filter. The tail fiber of the polarizer is welded with one end of the polarization maintaining fiber ring. The other end of the polarization maintaining fiber ring is welded with the temperature sensing head. The G end of the F-P tunable filter is welded with the input end of the photo detector. The output end of the photo detector is connected with the input end of the analog to digital converter. The output end of the analog to digital converter is connected with the input end of the signal processor. The wave shaped output end of the signal processor is connected with the F end of the F-P tunable filter. The temperature output end of the signal processor is used for delivering the temperature T. The F-P tunable filter connected between the fiber optic coupler and the photo detector can replace spectrometer to obtain the optical spectrum which simplifies the test operating procedure, is in favor for the processing of the signal information, and makes the sensor more practical. The temperature value T delivered by the temperature sensor and the spatial frequency fLambada are presents in a linear relationship. The temperature calculation can be simply and conveniently accomplished in the signal processor.
Description
Technical field
The present invention relates to a kind of fibre optic temperature sensor, more particularly, be meant a kind of fibre optic temperature sensor based on Wavelength demodulation.
Background technology
Utilize optical fiber sensing technology measurement temperature to compare and have its unique advantages with traditional electric signal temp measuring method, make the fibre optic temperature sensor in the environment of high electromagnetic interference (EMI), high pressure, high radiation, to work, thereby obtained development energetically and had widely using.
Patent No. ZL 200510085538.8, multi-channel optical fiber temperature sensor.Inventor Yang Yuan flood discloses optical path difference that a kind of transmission coefficient difference of two polarization modes that utilize polarization maintaining optical fibre produces temperature sensitivity has been realized the measurement of temperature in this part patent application document, each optical device adopts the fine antijamming capability that has improved sensor that connects of full polarization; Described multiple sensor also utilizes the polarization-maintaining fiber coil of different length to guarantee that the different temperatures sensing passage turns back to the asynchronism(-nization) of photodetector, thereby realizes the multichannel sensing.
Above-mentioned optical fiber temperature sensor is based on light intensity is detected with the single variation of temperature, and its output temperature value is subjected to the influence and the restriction of wide spectrum light source stability.
Summary of the invention
The purpose of this invention is to provide a kind of fibre optic temperature sensor based on Wavelength demodulation, the sawtooth wave that this temperature sensor produces by single-chip microcomputer on the one hand drives the F-P adjustable filter and enters mode of operation, simultaneously by the spectral information F of F-P adjustable filter to receiving
0Carry out filtering, calculate output temperature value T according to temperature model M on the other hand.Temperature sensor of the present invention has overcome the influence of the instability of light source to total system effectively, has eliminated the influence of the light intensity instabilities that reason caused such as device aging to total system stability and precision.
The present invention is a kind of fibre optic temperature sensor based on Wavelength demodulation, by wide spectrum light source, fiber coupler, the polarizer, and polarization-maintaining fiber coil, Temperature probe, F-P adjustable filter, photodetector, analog to digital converter and signal processor are formed; The tail optical fiber of wide spectrum light source and the welding of the A of fiber coupler end; The B end of fiber coupler and the fine welding of going into of the polarizer, the C end of fiber coupler is held welding with the E of F-P adjustable filter; One end welding of the tail optical fiber of the polarizer and polarization-maintaining fiber coil; The other end of polarization-maintaining fiber coil and Temperature probe welding; The G end of F-P adjustable filter and the input end welding of photodetector, the output terminal of photodetector links to each other with the input end of analog to digital converter, the output terminal of analog to digital converter links to each other with the input end of signal processor, the waveform output terminal of signal processor links to each other with the F of F-P adjustable filter end, and the temperature output terminal of signal processor is used for output temperature value T.Described signal processor internal memory contains wavelength-temperature relation module, and this wavelength-temperature relation module is resolved the unit by sawtooth wave generation unit, Fourier transformation unit and temperature and constituted.
Fibre optic temperature sensor of the present invention is the wavelength information of wide spectrum light source output to be carried out demodulation process obtain sensor output temperature value.Being connected with the F-P adjustable filter between fiber coupler and photodetector can replace spectrometer to obtain spectrum having simplified test operating procedure, helped the processing of signal message, made it more trend towards practicability.The output temperature value T of temperature sensor of the present invention and spatial frequency f
λBetween be linear relationship, can in signal processor, finish resolving of temperature simply and easily.Temperature sensor of the present invention has overcome the influence of the instability of light source to sensor-based system, has solved effectively because the device loss that device aging or installation etc. bring changes and light source floats to cause the influence of light intensity instability to measuring accuracy and stability.
Description of drawings
Fig. 1 is a fibre optic temperature sensor structural representation of the present invention.
Embodiment
The present invention is described in further detail below in conjunction with accompanying drawing.
The present invention is a kind of fibre optic temperature sensor based on the Wavelength demodulation detection mode, has adopted single-chip microcomputer output sawtooth wave to drive the F-P adjustable filter and has obtained spectral information, according to output temperature value T and spatial frequency f
λBetween linear relationship realize that real time temperature measures.
See also shown in Figure 1, a kind of fibre optic temperature sensor of the present invention is by wide spectrum light source, fiber coupler, the polarizer, polarization-maintaining fiber coil, Temperature probe, F-P (Fabry-Perot) adjustable filter, photodetector, analog to digital converter and signal processor are formed.The difference of fibre optic temperature sensor of the present invention and existing fiber temperature sensor is to be connected with between fiber coupler and the photodetector F-P adjustable filter.Signal processor adopts singlechip chip (C8051F060 type single-chip microcomputer), and will download in the single-chip microcomputer with wavelength-temperature relation module that the C language compilation constitutes, this wavelength-temperature relation module is resolved the unit by sawtooth wave generation unit, Fourier transformation unit and temperature and is constituted.
The annexation of fibre optic temperature sensor of the present invention is: the tail optical fiber of wide spectrum light source and (going into fibre for one of the fiber coupler) welding of the A of fiber coupler end; The B end (tail optical fiber of fiber coupler) of fiber coupler and the fine welding of going into of the polarizer, (another root of fiber coupler is gone into E end welding fine and the F-P adjustable filter to the C end of fiber coupler; One end welding of the tail optical fiber of the polarizer and polarization-maintaining fiber coil; The other end of polarization-maintaining fiber coil and Temperature probe welding; The G end (output terminal) of F-P adjustable filter and the input end welding of photodetector, the output terminal of photodetector links to each other with the input end of analog to digital converter, the output terminal of analog to digital converter links to each other with the input end of signal processor, the waveform output terminal of signal processor links to each other with the F of F-P adjustable filter end, and the temperature output terminal of signal processor is used for output temperature value T.
In the present invention, after fibre optic temperature sensor powered on, it was that 0～5V is adjustable that the sawtooth wave generation unit in the signal processor (C8051F060 type single-chip microcomputer) will produce output voltage amplitude, the sawtooth waveform signal N of frequency 10～100Hz.This sawtooth waveform signal N is used for driving the F-P adjustable filter and enters mode of operation.
In the present invention, the F-P adjustable filter is used to receive the spectral information F of fiber coupler output
0, and to spectral information F
0The output intensity information f is given photodetector after carrying out Filtering Processing; Photodetector carries out exporting electric signal D after the opto-electronic conversion to the intensity signal f that receives
0Give analog to digital converter; The electric signal D of analog to digital converter to receiving
0Output digital electric signal D gives signal processor after carrying out analog to digital conversion; Signal processor is introduced into the digital electric signal D that receives and carries out Fourier transform processing acquisition spatial frequency f in the Fourier transformation unit
λ, spatial frequency f then
λEntering temperature resolves in the unit and obtains output temperature value T according to temperature model M.
Described temperature model
Middle f
λThe representation space frequency, λ represents the centre wavelength of wide spectrum light source emergent light, the length of L representation temperature sensing head, C
1, C
2The temperature coefficient of the selected polarization maintaining optical fibre of expression Temperature probe, and C
1≠ C
2
In the present invention, wide spectrum light source adopts Er-Doped superfluorescent fiber source (SFS), and its centre wavelength is 1545nm, and output power is greater than 10mW, and bandwidth is greater than 40nm.
In the present invention, polarization-maintaining fiber coil and Temperature probe are chosen panda type polarization-preserving fiber, and loss is 1.1dB/km.
In the present invention, fiber coupler adopts the single-mode optical-fibre coupler of 50/50 beam split of typical 4 port organizations, and A end, C end are generally the optical fibre input end of fiber coupler, and the B end is the tail optical fiber end of fiber coupler.Operation wavelength 1550nm, typical additive loss 0.07dB inserts loss less than 3.4dB.
In the present invention, the polarizer adopts grinding and polishing method processing and fabricating, has all optical fibre structure, and operation wavelength is at 1550nm, extinction ratio 20dB, and the insertion loss is 0.7dB.
In the present invention, photodetector adopts the PFTM911 type InGaAs planar structure PIN-FET detector of Wuhan Telecommunication Devices Co., Ltd.Its bandwidth is 7MHz, and sensitivity is to the maximum-51dBm, and modulation rate is 8.40～10Mb/s, and transimpedance is 1300k.
In the present invention, the F-P adjustable filter has adopted the TF074D type F-P adjustable filter that Micron Optics company produces.It is under the condition of 1550nm at the test wavelength, and Free Spectral Range is 106nm, and bandwidth is 0.017nm.Tunable optic filter allows wavelength to have the light of multiple relation to pass through with the F-P cavity length, and the light of other wavelength is pressed the Airy function decay.Have the function of filtering based on this principle of work F-P adjustable filter, can obtain the spectrum in certain wavelength coverage, replaced spectrometer, make temperature sensor become lighter, trend towards practicability.TF074D type F-P adjustable filter also has high-accuracy high-resolution, Heat stability is good, the characteristics of shock resistance and vibration simultaneously.
In the present invention, signal processor adopts the C8051F060 type single-chip microcomputer of CYGNAL company, this single-chip microcomputer is fully-integrated mixed signal SOC (system on a chip) type MCU, on the sheet High Speed Microcontroller comprised at a high speed, the CIP-51 kernel of pipeline organization, but control such as the ram in slice of the 64KB FLASH storer of in-system programming, 4352 (4K+256) byte and the external data memory interface of addressable 64KB address space nuclear.Be loaded with wavelength-temperature relation module that utilization C language compilation constitutes in this single-chip microcomputer down, this wavelength-temperature relation module resolves the unit by sawtooth wave generation unit, temperature and Fourier transformation unit constitutes.
Embodiment
It is in 40 ℃ the working environment that fibre optic temperature sensor of the present invention is applied to temperature, carries out temperature test.
The configuration of fibre optic temperature sensor: the Temperature probe length L is 0.183m, the temperature coefficient C of Temperature probe (panda type polarization-preserving fiber)
1Be-2.01 * 10
-3, C
2Be 8.608 * 10
-2, the central wavelength lambda of wide spectrum light source emergent light is 1545nm, spatial frequency f
λ=0.9325 * 10
9, T=39.8 ℃ of output temperature value
The processing procedure of fibre optic temperature sensor:
(1) after fibre optic temperature sensor powered on, wide spectrum light source drove under the drive signal of exporting at light source and enters duty, and wide spectrum light source output light (central wavelength lambda is 1545nm) is given fiber coupler;
(2) output light becomes linearly polarized light behind fiber coupler, the polarizer; This linearly polarized light enters Temperature probe along the polarization principal axis transmission of polarization maintaining optical fibre, the linearly polarized light that enters Temperature probe evokes two polarization modes in sensing head and (an end welding of Temperature probe is at an end of polarization maintaining optical fibre at the other end of sensing head, the other end end face of Temperature probe is coated with reflectance coating, thereby can play the effect of reflected ray polarized light) the end all reflected;
(3) linearly polarized light that returns of Yan Yuanlu enters behind coupling mechanism in the F-P adjustable filter;
(4) the F-P adjustable filter is under the control of the sawtooth wave drive signal N of signal processor output, to spectral information F
0The output intensity information f is given photodetector after carrying out Filtering Processing.This photodetector carries out exporting electric signal D after the opto-electronic conversion to the intensity signal f that receives
0Give analog to digital converter; The electric signal D of analog to digital converter to receiving
0Output digital electric signal D gives signal processor after carrying out analog to digital conversion.Signal processor is introduced into digital electric signal D and carries out Fourier transform processing acquisition spatial frequency f in the Fourier transformation unit
λ, spatial frequency f then
λEntering temperature resolves in the unit according to temperature model
Obtain output temperature value T.
The detection method based on Wavelength demodulation of fibre optic temperature sensor of the present invention has overcome the influence of the instability of light source to total system effectively, has eliminated the influence of the light intensity instabilities that reason caused such as device aging to total system stability and precision.This method is utilized temperature T and spatial frequency f
λBetween linear relationship can in signal processor, calculate temperature value simply and easily.F-P adjustable filter replacement spectrometer obtains spectrum and has simplified test operating procedure, helps the processing of signal message, makes it more trend towards practicability.
Claims (9)
1, a kind of fibre optic temperature sensor based on Wavelength demodulation is characterized in that: by wide spectrum light source, fiber coupler, the polarizer, and polarization-maintaining fiber coil, Temperature probe, F-P adjustable filter, photodetector, analog to digital converter and signal processor are formed; The tail optical fiber of wide spectrum light source and the welding of the A of fiber coupler end; The B end of fiber coupler and the fine welding of going into of the polarizer, the C end of fiber coupler is held welding with the E of F-P adjustable filter; One end welding of the tail optical fiber of the polarizer and polarization-maintaining fiber coil; The other end of polarization-maintaining fiber coil and Temperature probe welding; The G end of F-P adjustable filter and the input end welding of photodetector, the output terminal of photodetector links to each other with the input end of analog to digital converter, the output terminal of analog to digital converter links to each other with the input end of signal processor, the waveform output terminal of signal processor links to each other with the F of F-P adjustable filter end, and the temperature output terminal of signal processor is used for output temperature value T;
Described signal processor internal memory contains wavelength-temperature relation module, and this wavelength-temperature relation module is resolved the unit by sawtooth wave generation unit, Fourier transformation unit and temperature and constituted;
Described F-P adjustable filter is used to receive the spectral information F of fiber coupler output
0, and to spectral information F
0The output intensity information f is given photodetector after carrying out Filtering Processing; Photodetector carries out exporting electric signal D after the opto-electronic conversion to the intensity signal f that receives
0Give analog to digital converter; The electric signal D of analog to digital converter to receiving
0Output digital electric signal D gives signal processor after carrying out analog to digital conversion; Signal processor is introduced into the digital electric signal D that receives and carries out Fourier transform processing acquisition spatial frequency f in the Fourier transformation unit
λ, spatial frequency f then
λEntering temperature resolves in the unit and obtains output temperature value T according to temperature model M.
2, the fibre optic temperature sensor based on Wavelength demodulation according to claim 1 is characterized in that: described temperature model
Middle f
λThe representation space frequency, λ represents the centre wavelength of wide spectrum light source emergent light, the length of L representation temperature sensing head, C
1, C
2The temperature coefficient of the selected polarization maintaining optical fibre of expression Temperature probe, and C
1≠ C
2
3, the fibre optic temperature sensor based on Wavelength demodulation according to claim 1 is characterized in that: signal processor adopts single-chip microcomputer C8051F060 chip.
4, the fibre optic temperature sensor based on Wavelength demodulation according to claim 1 is characterized in that: the F-P adjustable filter is that Free Spectral Range is 106nm under the condition of 1550nm at wavelength, and bandwidth is 0.017nm.
5, the fibre optic temperature sensor based on Wavelength demodulation according to claim 1 is characterized in that: it is that 0～5V is adjustable that the sawtooth wave generation unit in the signal processor will produce output voltage amplitude, the sawtooth waveform signal N of frequency 10～100Hz.
6, the fibre optic temperature sensor based on Wavelength demodulation according to claim 1 is characterized in that: wide spectrum light source adopts Er-Doped superfluorescent fiber source, and centre wavelength is 1545nm, and output power is greater than 10mW, and bandwidth is greater than 40nm.
7, the fibre optic temperature sensor based on Wavelength demodulation according to claim 1, it is characterized in that: polarization-maintaining fiber coil and Temperature probe are chosen panda type polarization-preserving fiber, and loss is 1.1dB/km.
8, the fibre optic temperature sensor based on Wavelength demodulation according to claim 1, it is characterized in that: fiber coupler adopts the single-mode optical-fibre coupler of 50/50 beam split, operation wavelength 1550nm.
9, the fibre optic temperature sensor based on Wavelength demodulation according to claim 1 is characterized in that: the operation wavelength of the polarizer is at 1550nm, extinction ratio 20dB.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810222875A CN100587427C (en) | 2008-09-24 | 2008-09-24 | Optical fiber temperature sensor based on wave length demodulation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810222875A CN100587427C (en) | 2008-09-24 | 2008-09-24 | Optical fiber temperature sensor based on wave length demodulation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101377441A true CN101377441A (en) | 2009-03-04 |
| CN100587427C CN100587427C (en) | 2010-02-03 |
Family
ID=40421089
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200810222875A Expired - Fee Related CN100587427C (en) | 2008-09-24 | 2008-09-24 | Optical fiber temperature sensor based on wave length demodulation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100587427C (en) |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101949744A (en) * | 2010-09-06 | 2011-01-19 | 国网电力科学研究院武汉南瑞有限责任公司 | Fiber grating-based transformer internal temperature detection system |
| CN101639387B (en) * | 2009-09-11 | 2011-06-01 | 北京航空航天大学 | Optical fiber temperature sensor for detection based on wavelength corresponding to extreme value and temperature sensing method |
| CN101706329B (en) * | 2009-12-01 | 2011-08-31 | 北京齐瑞得电力技术有限公司 | Optical fiber temperature sensor |
| CN102288325B (en) * | 2009-12-01 | 2012-11-14 | 北京齐瑞德光电科技有限公司 | Optical fiber temperature sensor |
| CN103438882A (en) * | 2013-08-30 | 2013-12-11 | 中国兵器工业导航与控制技术研究所 | Fiber-optic gyroscope with low scale factor error |
| CN103776475A (en) * | 2014-01-28 | 2014-05-07 | 浙江大学 | Optical fiber sensor and sensing method based on linear filter and photoelectric detector |
| CN105974172A (en) * | 2016-06-01 | 2016-09-28 | 南京南瑞继保电气有限公司 | All-fiber current transformer based on polarization maintaining fiber temperature sensor |
| CN106482862A (en) * | 2016-09-29 | 2017-03-08 | 西安交通大学 | A kind of demodulation method of optical fiber F P temperature sensor and system |
| CN108225604A (en) * | 2017-12-29 | 2018-06-29 | 长园深瑞继保自动化有限公司 | Optical fiber temperature-measurement sensing head, temperature measuring equipment and temp measuring method |
| CN108577964A (en) * | 2018-04-25 | 2018-09-28 | 南京市口腔医院 | Semiconductor laser therapeutic instrument, control method and temperature signal processing method |
| CN111735554A (en) * | 2020-08-12 | 2020-10-02 | 国网四川省电力公司成都供电公司 | Distributed optical fiber temperature measurement system and method for oil-immersed power transformer |
| CN113050727A (en) * | 2021-03-18 | 2021-06-29 | 北京航空航天大学 | Atomic air chamber temperature control system based on high-precision polarization maintaining optical fiber |
-
2008
- 2008-09-24 CN CN200810222875A patent/CN100587427C/en not_active Expired - Fee Related
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101639387B (en) * | 2009-09-11 | 2011-06-01 | 北京航空航天大学 | Optical fiber temperature sensor for detection based on wavelength corresponding to extreme value and temperature sensing method |
| CN101706329B (en) * | 2009-12-01 | 2011-08-31 | 北京齐瑞得电力技术有限公司 | Optical fiber temperature sensor |
| CN102288325B (en) * | 2009-12-01 | 2012-11-14 | 北京齐瑞德光电科技有限公司 | Optical fiber temperature sensor |
| CN101949744B (en) * | 2010-09-06 | 2012-08-08 | 国网电力科学研究院武汉南瑞有限责任公司 | Fiber grating-based transformer internal temperature detection system |
| CN101949744A (en) * | 2010-09-06 | 2011-01-19 | 国网电力科学研究院武汉南瑞有限责任公司 | Fiber grating-based transformer internal temperature detection system |
| CN103438882B (en) * | 2013-08-30 | 2016-02-10 | 中国兵器工业导航与控制技术研究所 | A kind of optical fibre gyro of low scale factor error |
| CN103438882A (en) * | 2013-08-30 | 2013-12-11 | 中国兵器工业导航与控制技术研究所 | Fiber-optic gyroscope with low scale factor error |
| CN103776475A (en) * | 2014-01-28 | 2014-05-07 | 浙江大学 | Optical fiber sensor and sensing method based on linear filter and photoelectric detector |
| CN105974172A (en) * | 2016-06-01 | 2016-09-28 | 南京南瑞继保电气有限公司 | All-fiber current transformer based on polarization maintaining fiber temperature sensor |
| CN106482862A (en) * | 2016-09-29 | 2017-03-08 | 西安交通大学 | A kind of demodulation method of optical fiber F P temperature sensor and system |
| CN108225604A (en) * | 2017-12-29 | 2018-06-29 | 长园深瑞继保自动化有限公司 | Optical fiber temperature-measurement sensing head, temperature measuring equipment and temp measuring method |
| CN108577964A (en) * | 2018-04-25 | 2018-09-28 | 南京市口腔医院 | Semiconductor laser therapeutic instrument, control method and temperature signal processing method |
| CN111735554A (en) * | 2020-08-12 | 2020-10-02 | 国网四川省电力公司成都供电公司 | Distributed optical fiber temperature measurement system and method for oil-immersed power transformer |
| CN113050727A (en) * | 2021-03-18 | 2021-06-29 | 北京航空航天大学 | Atomic air chamber temperature control system based on high-precision polarization maintaining optical fiber |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100587427C (en) | 2010-02-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100587427C (en) | Optical fiber temperature sensor based on wave length demodulation | |
| CN103712689B (en) | Continuous laser device spectral line width measurement device based on optical frequency comb | |
| CN102279095B (en) | Device for reducing influence of birefringent chromatic dispersion on polarization coupling measurement of polarization maintaining optical fiber | |
| CN101592551B (en) | Sagnac interferometer-based method and Sagnac interferometer-based device for testing beat length of polarization maintaining optical fiber | |
| CN108106643A (en) | Ultrafast distributed Brillouin Optical time-domain analysis instrument based on optics chirp chain | |
| CN103017687A (en) | Orthogonal polarization fiber bragg grating vector torsion sensing device and detection method thereof | |
| CN101290248B (en) | Single-mode infra-red wavemeter based on Mach-Zehnder Interferometer filtering principle | |
| CN103674497A (en) | High accuracy measurement system of line width of narrow line width laser | |
| CN104459267A (en) | Thin film type all-fiber current transformer with temperature compensation | |
| CN103900680A (en) | Device and detecting method for restraining polarization crosstalk measuring noise by the adoption of light source | |
| CN104111086A (en) | Low-Brillouin scattering threshold sensing fiber-based optical time domain reflectometer device and method | |
| CN207557107U (en) | A kind of cavity ring-down spectroscopy humidity measurement system based on intracavitary amplification | |
| CN101639387A (en) | Optical fiber temperature sensor for detection based on wavelength corresponding to extreme value and temperature sensing method | |
| CN101706329A (en) | Optical fiber temperature sensor | |
| CN105628174A (en) | Optical fiber F-P sensor vibration demodulation system based on polarization switching | |
| CN105806374A (en) | Fiber bragg grating wavelength demodulation method | |
| CN107356412B (en) | A kind of measurement method of the measuring system based on rare-earth doped optical fibre refractive index | |
| CN105953919A (en) | All-fiber Fourier expansion spectrum analyzer | |
| CN203719878U (en) | A narrow linewidth laser linewidth high precision measurement system | |
| CN105241550A (en) | All-fiber Fourier transform Raman spectrometer | |
| CN109001155A (en) | A kind of humidity measuring method based on low gain low noise optical fiber cavity attenuation and vibration technique | |
| CN209746025U (en) | Current measurement system based on double fiber bragg gratings | |
| CN103344184B (en) | Based on the wavelength-division of the mixing certainly multiplexed multi-channel displacement sensing system of linear cavity multi-wavelength optical fiber laser | |
| CN205583362U (en) | Single -frequency fiber laser mode hopping monitoring system based on single -photon detection | |
| CN212482511U (en) | Device based on cavity ring-down large-range high-precision fiber grating sensing |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100203 Termination date: 20110924 |