CN201204380Y - Fibre-optical grating multiplexing demodulating equipment base on Fourier domain mode-locked laser - Google Patents
Fibre-optical grating multiplexing demodulating equipment base on Fourier domain mode-locked laser Download PDFInfo
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- CN201204380Y CN201204380Y CNU2008200867806U CN200820086780U CN201204380Y CN 201204380 Y CN201204380 Y CN 201204380Y CN U2008200867806 U CNU2008200867806 U CN U2008200867806U CN 200820086780 U CN200820086780 U CN 200820086780U CN 201204380 Y CN201204380 Y CN 201204380Y
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Abstract
The utility model relates to a optical fiber grating multiplex demodulating apparatus of a Fourier domain mode-locked laser. Presently, the active type multi optical fiber grating multiplex demodulating apparatus is incomplete. The demodulating apparatus of the utility model comprises an optical amplifier connected to be a annular structure by optical fiber, an optical isolator, a tunable filter, an optical circulator and a three-terminal optical fiber coupler. An input terminal of the three-terminal optical fiber coupler is connected with the optical circulator, a power big factorized output terminal is connected with a photoelectric probe by the optical fiber. The optical circulator is connected in series with multi optical fiber grating groups to form an optical fiber grating sensing network connection, each optical fiber grating group is formed by multi optical fiber grating with different center wavelength in series connection. The device of the utility model can be used for temperature and stress sensor, and has advantages of high resolution, big measuring band-width, high demodulation precision and low cost.
Description
Technical field
The utility model belongs to technical field of optical fiber sensing, particularly a kind of optical fiber optical grating multiplexing demodulation device of Fourier domain mode-locking laser.
Background technology
At sensory field of optic fibre, fiber grating is because it is very responsive to temperature, STRESS VARIATION, and have that volume is little, optical fiber is compatible, be not subjected to electromagnetic interference and can multi-point sensing etc. advantage, become crucial senser element in the industry.Fibre Optical Sensor is than the sensing of common electricity, and its biggest advantage is to realize the distributed sensing of system's multiple spot, and fiber grating can directly a plurality of optical fiber that write as sensing head.This is in such optical fiber sensing system, its most the technology of core be exactly multiplexing demodulation to a plurality of fiber gratings.Therefore, it is significant to research and develop effective optical fiber optical grating multiplexing demodulation method.
The a plurality of optical fiber optical grating multiplexing demodulation system that is used for sensing can be divided into two big classes substantially: the one, and a plurality of optical fiber optical grating multiplexing demodulation system of passive-type; The 2nd, active a plurality of optical fiber optical grating multiplexing demodulation system.The former adopts wideband light source and FP filter or matched fiber grating, array waveguide grating or other the filtering device that can scan usually, and this system exists that the light source utilance is low, signal to noise ratio is low or shortcoming such as a plurality of probes of needs.The latter fiber grating feedback constitutes Optical Maser System, and the wavelength signals from laser output extraction fiber grating has light source utilance height, signal to noise ratio advantages of higher, but does not also have this perfect type systematic at present.
Summary of the invention
The utility model is exactly at the deficiencies in the prior art, has proposed a kind of multipoint multiplexing and demodulating equipment of fiber grating of Fourier domain mode-locking laser.
The utility model comprises image intensifer, optical isolator, tunable optic filter, optical circulator, the three fiber port couplers that connect into loop configuration by optical fiber, wherein an end of image intensifer is connected with the input of optical isolator, the output of optical isolator is connected with an end of tunable optic filter, the other end of tunable optic filter is connected with first port of optical circulator, the 3rd port of optical circulator is connected with the input of three fiber port couplers, and the big proportion by subtraction output of the power of three fiber port couplers is connected with the other end of image intensifer; Signal generator is connected with the driving port of tunable optic filter; The little proportion by subtraction output of the power of three fiber port couplers is connected with photoelectric probe by optical fiber, and data collecting card is connected by lead with photoelectric probe; Second port of optical circulator is connected with the optical fiber grating sensing network that is in series by a plurality of fiber grating groups, and each fiber grating group is in series by the fiber grating of a plurality of different centre wavelengths.
The utility model mainly is applicable to the multiplexing and demodulation of the fiber grating of a plurality of Application in Sensing, the wavelength shift of fiber grating is converted into the time domain pulse interval, determine the wavelength shift of fiber grating according to the time domain pulse interval of measuring, and the relation of the wavelength shift of fiber grating and temperature and stress has been well known, so the utility model can be applied to temperature and stress sensing.The maximum demodulation number of channel of the present utility model reaches hundreds of, has advantage with low cost, is fit to integrated, instrumentation and networking.
Description of drawings
Fig. 1 is an overall structure schematic diagram of the present utility model.
Embodiment
As shown in Figure 1, one end of image intensifer 1 is connected with the input of optical isolator 9, the output of optical isolator 9 is connected with an end of tunable optic filter 7, the other end of tunable optic filter 7 is connected with first port of optical circulator 5, the 3rd port of optical circulator 5 is connected with the input of three fiber port couplers 4, and the big proportion by subtraction of the power of three fiber port couplers 4 (90%) output is connected with the other end of image intensifer 1.Signal generator 8 is connected with the driving port of tunable optic filter 7.The little proportion by subtraction of the power of three fiber port couplers 4 (10%) output is connected with photoelectric probe 2 by optical fiber, and data collecting card 3 and photoelectric probe 2 are connected by lead.Second port of optical circulator 5 is connected with the optical fiber grating sensing network that is in series by 2 fiber grating groups 6, and each fiber grating group 6 is in series by the fiber grating of 2 different centre wavelengths.
Concrete multiplexing demodulation method is:
(1) the 1st fiber grating group is respectively 1547.8nm by centre wavelength, and 1548.9nm, reflectivity are two fiber gratings compositions of 95%, record the long M in resonant cavity chamber that the 1st fiber grating group feedback forms
1=5.34km, the frequency f of the output triangular wave of the signal generator of the device of definite driving tunable optic filter
1=37.432kHz; The 2nd fiber grating group is respectively 1547.8nm by centre wavelength, and 1546.7nm, reflectivity are two fiber gratings compositions of 95%, record the long M in resonant cavity chamber that the 2nd fiber grating group feedback forms
2=6.94km, the frequency f of the output triangular wave of the signal generator of the device of definite driving tunable optic filter
2=28.776kHz;
(2) data collecting card obtains the output signal of resonant laser light by photoelectric probe;
Two pulses appear in the corresponding resonant laser light output signal of each fiber grating in (3) the i fiber grating group in a scan period of tunable optic filter, time interval variation delta t and optic fiber grating wavelength drift value Δ λ between two pulses satisfy following linear relationship:
Wherein W=6nm is the tunable optic filter sweep limits, measures the time interval variation delta t between two pulses, calculates the centre wavelength drift value of fiber grating in corresponding each fiber grating group according to following formula.
The wavelength shift of the centre wavelength by fiber grating can obtain the variation (variations such as little curved, temperature, stress) to the environment of inductive sensing.This device utilizes the tunable optic filter modulation, realize the Fourier mode-lock operation of the corresponding particular fiber grating feedback of laser, transfer the wavelength signals of fiber grating the time domain impulsive signals of laser output to, thereby realized the transformation from the wavelength measurement to the time measurement; Corresponding particular drive output frequency, can realize a plurality of fiber grating demodulations that the position is approaching, and change the driver output frequency, can be to the diverse location fiber grating demodulation, so this device has been realized the approaching a plurality of optical fiber optical grating multiplexing demodulations of diverse location or position.
Claims (1)
1, optical fiber optical grating multiplexing demodulation device based on Fourier domain mode-locking laser, comprise image intensifer, optical isolator, tunable optic filter, optical circulator, three fiber port couplers, it is characterized in that: an end of image intensifer is connected with the input of optical isolator, the output of optical isolator is connected with an end of tunable optic filter, the other end of tunable optic filter is connected with first port of optical circulator, the 3rd port of optical circulator is connected with the input of three fiber port couplers, and the big proportion by subtraction output of the power of three fiber port couplers is connected with the other end of image intensifer; Signal generator is connected with the driving port of tunable optic filter; The little proportion by subtraction output of the power of three fiber port couplers is connected with photoelectric probe by optical fiber, and data collecting card is connected by lead with photoelectric probe; Second port of optical circulator is connected with the optical fiber grating sensing network that is in series by a plurality of fiber grating groups, and each fiber grating group is in series by the fiber grating of a plurality of different centre wavelengths.
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| Application Number | Priority Date | Filing Date | Title |
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| CNU2008200867806U CN201204380Y (en) | 2008-05-05 | 2008-05-05 | Fibre-optical grating multiplexing demodulating equipment base on Fourier domain mode-locked laser |
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| Application Number | Priority Date | Filing Date | Title |
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| CNU2008200867806U CN201204380Y (en) | 2008-05-05 | 2008-05-05 | Fibre-optical grating multiplexing demodulating equipment base on Fourier domain mode-locked laser |
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| CN201204380Y true CN201204380Y (en) | 2009-03-04 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102494801A (en) * | 2011-12-07 | 2012-06-13 | 电子科技大学 | Distributed optical delay optical fiber temperature sensor |
| CN102853858A (en) * | 2012-10-09 | 2013-01-02 | 成都阜特科技股份有限公司 | Fibre grating sensing device |
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2008
- 2008-05-05 CN CNU2008200867806U patent/CN201204380Y/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102494801A (en) * | 2011-12-07 | 2012-06-13 | 电子科技大学 | Distributed optical delay optical fiber temperature sensor |
| CN102853858A (en) * | 2012-10-09 | 2013-01-02 | 成都阜特科技股份有限公司 | Fibre grating sensing device |
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| 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: 20090304 |