Implement device and implementation method based on the big capacity self-healing optical fiber sensor network of spectral type Fibre Optical Sensor
[technical field]:
The invention belongs to a kind of optical fiber sensing network technical field, but relate in particular to having big capacity self-healing and can measuring the sensor network system of a plurality of parameters simultaneously of a kind of spectral characteristic based on Fibre Optical Sensor.
[background technology]:
Sensing technology is one of three big pillars of information industry.Optical fiber sensing technology is in the forward position of sensing technology development always.
Fibre Optical Sensor can be divided into functional form and not function type by sensing principle.The former optical fiber as senser, the latter optical fiber only as transmission medium.In functional Fibre-Optic Sensors, change light intensity (amplitude), phase place, polarization state and wavelength (frequency) in the optical fiber according to extraneous factor, and be divided into intensity type, phase type, polarization-type and spectral type Fibre Optical Sensor.At present the higher Fibre Optical Sensor of precision uses its spectral characteristic mostly, and biology sensor for example utilizes the Transflective characteristic of spectrum.Optical fiber Bragg grating sensor commonly used utilizes the mobile sensing of carrying out of Bragg centre wavelength.The Raman transducer utilizes the peak difference of optical fiber both sides Raman spectrum to carry out sensing.The Brillouin sensing device utilizes Brillouin's wavelength change to carry out sensing.The spectral type Fibre Optical Sensor utilizes wavelength information to carry out sensing, then can utilize wavelength-division multiplex technique WDM (Wavelength-division Multiplexing) to make up sensing network.
Optical fiber sensor network still rests on comparatively simple Fibre Optical Sensor at present and is connected in series and extension phase in parallel on this basis, no matter from its employed number of sensors, still consider from its network topology aspect, all remain further to be improved, promptly large-scale intelligent optical fiber sensor network does not also form.Many scientific research institutions have proposed several different methods, in order to improve the capacity of optical fiber sensor network.As application number is that 200710019914.2 patent of invention " has the fiber Bragg grating sensor network that survivability guarantees ", mentions the network topology that employing comprises the fan-shaped subnet structure of two-stage at least in this patent application, and the two-stage subnet all adopts sub-net module.Every grade of sub-net module all comprises host node, from node, and the transmission branch road, the sensing branch road, subnets at different levels are controlled it by optical switch.The network topology of fan-shaped subnet structure is relatively more novel, and the survivability that this method has improved optical fiber sensor network greatly guarantees that multiplexing number of sensors also increases to some extent, but the capacity of sensing net is not expanded on big degree.United States Patent (USP) " Large scale high speed multiplexed optical fiber sensor network ", the patent No. is US 6492636, mention the capacity that the method for using space division multiplexing and wavelength division multiplexing enlarges the sensing net in the application, improve the sensing speed of sensing net.But this kind method can increase the cost of sensor-based system greatly.
[summary of the invention]:
The objective of the invention is to solve the limited problem of senser element number in the optical fiber sensing network, propose a kind of implement device and implementation method of the big capacity self-healing optical fiber sensor network based on the spectral type Fibre Optical Sensor.The present invention can make full use of the spectrum resource of sensor-based system.
The implement device of the big capacity self-healing optical fiber sensor network based on the spectral type Fibre Optical Sensor provided by the invention, comprise light source, the light that sends from light source is connected with n (gross energy of Maxn=light source/every layer of energy that the sensing subnet is required) layer sensing subnet respectively through coupler, after a plurality of wavelength information of each sensing subnet output are changed by the multi-wavelength converter, be input in the wavelength division multiplexer through working optical fibre, through in an optical fiber, transmitting behind the wavelength multiplexing, be input to computer through the receiving demodulation device at last.
Between multi-wavelength converter that is connected with each sensing subnet and wavelength division multiplexer, respectively be equipped with a standby optical fiber.Between two adjacent sensing subnets, respectively add a cross-connect.
When the working optical fibre of certain layer of sensing subnet breaks down, can exchange to the transducing signal of this sensing subnet in the standby optical fiber by the multi-wavelength converter and transmit.If working optical fibre and standby optical fiber all break down, then the transducing signal of this sensing subnet can insert in the adjacent Fibre Optical Sensor subnet by the cross-connect between the sensing layer adjacent with this sensing layer and transmit, so just guaranteed the operate as normal of sensing network, make network have survivability and guarantee, but have self-healing property.
Wherein, light source is wide spectrum tunable optical source.
Described each sensing subnet is to be made of one group of Fibre Optical Sensor, and the topological structure of different sensing subnets is separate.The structure of each sensing subnet can be annular, star, tree-like or bus-type; Described Fibre Optical Sensor can be spectral type Fibre Optical Sensor, fiber-optic grating sensor, Raman Fibre Optical Sensor, Brillouin light fiber sensor, photon crystal optical fiber sensing device or biochemical sensor, and measurand can be temperature, stress, vibration, displacement, rotation, electromagnetic field, chemistry amount or biomass.
The present invention provides a kind of implementation method of the big capacity self-healing optical fiber sensor network based on the spectral type Fibre Optical Sensor simultaneously, this method adopts the implement device of above-described big capacity self-healing optical fiber sensor network based on the spectral type Fibre Optical Sensor to detect, and this method comprises following steps at least:
(1) optical fiber sensor network is arranged on the monitored target, system adopts wide spectrum tunable optical source, and spectrum is divided into the m section, total spectrum width/scanning resolution of Maxm=light source, the m section scans simultaneously, and the light beam that light source sends is all assigned to each sensing subnet behind coupler;
(2) obtain measured signal: the variation of the perception external environment that Fibre Optical Sensor is real-time, realize monitoring to monitored target, obtain the live signal of monitored target
The signal that (3) the 2nd steps obtained is to transmit with the form of wavelength division multiplexing, this wavelength-division multiplex signals is carried out wavelength conversion through Optical Fiber Transmission to wavelength shifter, thereby carry out time division multiplexing, obtains time multiplexing signal;
(4) time multiplexing signal with the different layers behind the 3rd step wavelength conversion transfers to wavelength division multiplexer through working optical fibre, carries out wavelength division multiplexing; When working optical fibre breaks down, enable the described time multiplexing signal of standby Optical Fiber Transmission, when breaking down simultaneously, working optical fibre and standby optical fiber enables optical cross-connect, described time multiplexing signal is exchanged in the adjacent sensing subnet, use the optical fiber of adjacent sensing subnet to transmit, therefore have survivability and guarantee;
(5) after the 4th step, the signal behind the wavelength division multiplexing transferred to the receiving demodulation device, carry out demodulation, and this signal is converted into digital signal;
(6) digital signal after the 5th step was transformed is carried out analytical calculation through Optical Fiber Transmission to computer, and the result shown or informs human observer in the mode of audible alarm, so that human observer takes measures to solve the problem of current appearance; Perhaps computer sends control command according to the state of current monitored target.
Advantage of the present invention and good effect:
(1) adopts Fibre Optical Sensor net implementation method of the present invention, every layer of sensing subnet can make full use of whole bandwidth of light source, the sensing net comprises n layer sensing subnet, just the number of sensors in the sensing net can be expanded to n doubly, therefore greatly expanded open ended Fibre Optical Sensor number in the optical fiber sensor network, realized jumbo optical fiber sensor network, and the sensing net only used a light source and a receiving demodulation device, the cost of system does not increase.
(2) transducer in every layer of Fibre Optical Sensor subnet can adopt all kinds such as fiber-optic grating sensor, Raman Fibre Optical Sensor, Brillouin light fiber sensor, photon crystal optical fiber sensing device, biochemical sensor, it can all be a certain Fibre Optical Sensor, it also can be the combination of multiple sensors type, as long as these transducers are that to utilize spectral characteristic to carry out sensing just passable, so optical fiber sensor network has the isomery characteristic.
(3) increased working optical fibre in this optical fiber sensor network, the cross-connect between standby optical fiber and every layer has guaranteed when optical fiber link breaks down, and optical fiber sensor network can also operate as normal, but makes network have viability, has self-healing property.
(4) light source is wide spectrum tunable optical source.The spectrum of wideband light source is divided into the m section, and this m section scans simultaneously, just can be shortening to original 1/m sweep time, and this will improve the sensing speed of sensing net greatly.
[description of drawings]:
Fig. 1 is a general structure block diagram of the present invention;
Wherein, the 1st, light source; 2 couplers; 3a, 3b ..., 3j ..., 3n sensing subnet; 4 cross-connects; 5 multi-wavelength converters; The 6a working optical fibre, the standby optical fiber of 6b; 7 wavelength division multiplexers (WDM); 8 receiving demodulation devices; 9 computers;
Fig. 2 is that 3 sections scanned schematic diagram simultaneously after the spectrum of C+L wave band scanning light source was divided into 3 sections;
Fig. 3 is every layer of sensing subnet structural representation;
Every layer of sensing net is made up of 25 different optical fiber Bragg grating sensors of centre wavelength, connects with bus type topological structure, and reflectance spectrum is changed by the multi-wavelength transformation device.The spectrum of 25 fiber-optic grating sensors has covered whole C+L-band;
Fig. 4 is the structural representation of specific embodiment optical fiber sensor network;
Among the figure, comprise the light source of C+L wave band, by 8 layers of bus-type sensing subnet that optical fiber Bragg raster constitutes, the multi-wavelength converter, optical cross-connection equipment, wavelength division multiplexer, Transmission Fibers, standby optical fiber, receiving demodulation device and computer are formed;
Fig. 5 wavelength information is changeed the temporal information schematic diagram; Wherein Fig. 5 a is the wavelength division multiplexing schematic diagram, and Fig. 5 b is the time division multiplexing schematic diagram;
Fig. 6 wavelength information is converted to the concrete enforcement schematic diagram of temporal information, and Fig. 6 a is the transmitted light spectrogram, and Fig. 6 b is the reverberation spectrogram; The ripple of expression specific wavelength only carries out wavelength conversion in the special time of period T.
[embodiment]:
Embodiment 1:
As shown in Figure 1, the implement device of optical fiber sensor network of the present invention is by light source, coupler, n layer sensing subnet (gross energy of Maxn=light source/every layer of energy that the sensing subnet is required), cross-connect, multi-wavelength transducer, wavelength division multiplexer, receiving demodulation device and computer are formed.Give n layer (gross energy of Maxn=light source/every layer of energy that the sensing subnet is required) sensing subnet 3 from the light that light source 1 sends through coupler 2, every layer of sensing subnet all can make full use of whole spectrum width resources of light source.Connect by cross-connect 4 between the sensing subnet.A plurality of wavelength information of each sensing subnet output are transformed in some specific wavelengths by multi-wavelength converter 5 to be transmitted, and wavelength information is converted to different strength informations constantly.The individual different wavelength information of n (gross energy of Maxn=light source/every layer of energy that the sensing subnet is required) connects in the incoming wave division multiplexer (WDM) 7 through working optical fibre 6a, through in an optical fiber, transmitting behind the wavelength multiplexing, be input in the computer 9 through receiving demodulation device 8, computer calculates by analysis.Just can know the information of each transducer institute sensing in the whole sensing network.Its overall construction drawing, as shown in Figure 1.
The structure of every layer of sensing subnet is separate, is to be linked together with annular, star, tree-like, bus-type or more complicated network configuration by a plurality of Fibre Optical Sensors.Fibre Optical Sensor can adopt the spectral type Fibre Optical Sensor, carry out sensing with regard to the spectral characteristic of utilizing each transducer like this, certainly also can adopt fiber-optic grating sensor, Raman Fibre Optical Sensor, Brillouin light fiber sensor, photon crystal optical fiber sensing device, biochemical sensor etc., but monitor temperature, stress, vibration, displacement, rotation, electromagnetic field, chemistry amount and biomass etc.Every layer network topology structure can be different in the n layer sensing subnet, and type of sensor and quantity also can be different.Every layer of available spectrum resource of sensing subnet is whole spectrum widths of light source.
Execute in the example of the present invention, at first optical fiber sensor network is arranged on the monitored target.System source adopts wide spectrum tunable optical source, and spectrum width covers the C+L (wave band of 1530nm~1620nm).We can be divided into 3 sections (m=3 this moment) 1530nm~1560nm to the C+L wave band, 1560nm~1590nm, and 1590~1620nm), these 3 sections can scan in one-period T simultaneously, as shown in Figure 2.So just can be original 1/3 shortening to sweep time, under other condition ideal situations, the sensing speed of sensing net becomes original 3 times accordingly.Coupler adopts 1 * 8 coupler of dividing equally.From the light beam that light source sends, all assign to (n=8 herein) in 8 sensing subnets by coupler.Transducer in the sensing subnet all adopts fiber grating FBG transducer, all is to utilize the center wavelength variation of the reflecting light of transducer to carry out the sensing of strain and temperature.Strain sensitivity is-1.2pm/ μ ε, temperature control is-13pm/ ℃, want the strain variation of 2000 μ ε of surveyed area and 100 ℃ variations in temperature, then the centre wavelength of each strain transducer is changed to 2.4nm, add the isolation strip of every each 0.8nm of limit, each strain transducer need occupy the bandwidth of 4nm.The centre wavelength of each temperature sensor be changed to 1.3nm, add the isolation strip of every each 0.35nm of limit, each temperature sensor need occupy the bandwidth of 2nm.Therefore 20 strain transducers and 5 temperature sensors have been comprised in every layer of sensing subnet.Every layer of sensing subnet all adopts bus topolopy that 25 Fiber Bragg Grating FBGs (FBG) transducer is coupled together, and utilizes the reflectance spectrum of fiber grating to carry out sensing, and the structure of each sublayer is all identical, and its structure as shown in Figure 3.
Optical fiber sensor network comprises 8 sensing subnets, the structure of each the sensing subnet all type with the Fibre Optical Sensor of first sensing subnet is identical with quantity, then whole optical fiber sensor network has 200 fiber-optic grating sensors (160 strain transducers wherein, 40 temperature sensors), the concrete enforcement figure of optical fiber sensor network as shown in Figure 4.
The centre wavelength of supposing first FBG transducer of every layer of sensing subnet is λ
1, the centre wavelength of the 2nd FBG transducer is λ
2, the centre wavelength of the 25th FBG transducer is λ
25, 25 altogether, preceding 20 are used to survey strain, and back 5 are used for the thermometric degree.
The light signal of every layer of Fibre Optical Sensor reflection transmits with the form of wavelength division multiplexing in an optical fiber because of the inconsistent of reflection kernel wavelength, carries out time division multiplexing after transforming through wavelength.The ripple of specific wavelength only carries out wavelength conversion in the particular moment of period T, and transverse axis becomes temporal information by wavelength information, as shown in Figure 5.The time multiplexing signal of the different layers behind the wavelength conversion transfers to wavelength division multiplexer through working optical fibre, carries out wavelength division multiplexing.When working optical fibre breaks down, enable the described time multiplexing signal of standby Optical Fiber Transmission, when breaking down simultaneously, working optical fibre and standby optical fiber enables optical cross-connect, described time multiplexing signal is exchanged in the adjacent sensing subnet, and signal transmits by the working optical fibre of adjacent sensing subnet.Then, wavelength-division multiplex signals to the receiving demodulation device, carries out receiving demodulation through Optical Fiber Transmission, and signal is converted into digital signal, so that computer carries out data analysis.Computer is according to the data of being analyzed, and whether display result or decision report to the police and transmitting control commands.
During extraneous measured changing, can cause that the centre wavelength of fiber-optic grating sensor changes.Centre wavelength as first first FBG that ties up was λ originally
1, but when extraneous factor changes (strain), this centre wavelength can be from λ
1Become λ
1+ Δ.By wavelength Conversion, its wavelength becomes λ
1'.Observe λ on the spectrometer
1' wave spectrum change, thereby determine be first the dimension transducer, experience strain and change.But specific to be first the dimension which transducer we determined by following method.
First dimension has 25 transducers, and the centre wavelength of each transducer is respectively: λ
1, λ
2... λ
25Therefore we correspond to the wave spectrum of light source (C+L wave band) on the time shaft t, different 25 the corresponding different constantly wavelength in the one-period T, as shown in Figure 6.λ
1Wavelength transform and to occur over just 0~T/25 in the time, λ
2Wavelength transform and to occur over just that T/25~2T/25 is in the time, the rest may be inferred, λ
25Variation occur over just 24T/25~T in the time, T is the needed time of scanning light source single pass.By analyzing λ
1Variation occur in period T what constantly, thereby which transducer impression of determining ground floor is extraneous measured, change has taken place in centre wavelength.From the spectrometer we can observe Δ ' big or small, again because Δ ' linear relationship is one to one arranged with Δ.We by analyze Δ ' size, thereby can know the size of Δ, and then can calculate extraneous measured concrete variation numerical value accurately, realize the function that detects.
In like manner, the transducer in n (n=1,2,3,4,5,6,7, the 8) layer we can be transformed to λ to centre wavelength by the multi-wavelength converter
n(n=1,2,3,4,5,6,7,8).See λ from spectrometer
nWhen changing, can determine is the signal that the transducer of n (n=1,2,3,4,5,6,7,8) layer transmits.Accurately locate the size of analytical calculation variable quantity again by the described method of the preceding paragraph.