CN210464387U - Large-scale composite material strain space high-density monitoring system - Google Patents
Large-scale composite material strain space high-density monitoring system Download PDFInfo
- Publication number
- CN210464387U CN210464387U CN201921583486.0U CN201921583486U CN210464387U CN 210464387 U CN210464387 U CN 210464387U CN 201921583486 U CN201921583486 U CN 201921583486U CN 210464387 U CN210464387 U CN 210464387U
- Authority
- CN
- China
- Prior art keywords
- optical fiber
- grating
- wavelength
- composite
- path
- 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
Images
Landscapes
- Length Measuring Devices By Optical Means (AREA)
Abstract
A large scale composite strain space high density monitoring system, the system comprising: the device comprises an optical fiber sensor, a scanning laser, a test interference light path, a signal acquisition module and a signal processing system. The optical fiber sensor is an optical fiber which is embedded in the composite material or attached to the surface of the composite material and is engraved with a spatial compact type equal-wavelength grating subarray composite array or a multi-wavelength grating subarray composite array; the scanning laser is a narrow linewidth wavelength linear scanning laser; the function of the test interference optical path comprises generating a reference interference signal and an interference signal carrying strain information; the signal acquisition module has the functions of wave decomposition, photoelectric conversion, analog signal acquisition and signal analog-to-digital conversion; the signal processing system comprises the functions of scanning laser control, acquisition module control, grating sensing signal digital processing and strain information analysis. The utility model discloses can realize the high space density monitoring of meeting an emergency on the large scale combined material.
Description
Technical Field
The utility model relates to a strain test field especially relates to a large scale combined material space high density monitoring system that meets an emergency.
Technical Field
Due to its superior properties, composite materials are widely used in the aerospace, marine, aviation, traffic, sports/leisure and civil engineering fields, especially in the aerospace field, and in order to improve the comprehensive properties of aircrafts and meet the flight requirements of higher performance, various aerospace aircrafts widely adopt large-scale, light-weight, thin-walled flexible composite materials. However, although the composite material has many benefits, due to the characteristics of complex material, large size, thinness, light weight and the like, the composite material is easy to generate structural vibration, deformation, fatigue and other problems under the action of an external environment, and brings about small potential safety hazards to the aircraft, so that the composite material needs to be subjected to real-time structural health monitoring during the ground performance detection and flight process of the aircraft, and the structural safety and performance defects of the material are detected, identified, positioned and evaluated in time, so that the composite material is effectively maintained and safely operated in real time.
Generally, if there is damage to the material structure that constitutes a safety and performance defect, the stress distribution around the damage point will change accordingly, so it can be determined whether there is damage by detecting the change of the strain distribution on the composite material. Compared with a thermocouple, a thermistor and the like, the fiber grating sensor is more suitable for high-precision strain sensing of large-scale composite materials due to the characteristics of high-density spatial multiplexing, light weight, insulation, easiness in embedding and the like. The conventional strain detection technology based on the grating sensor is influenced by the limitation of the wavelength scanning range of a light source or the problem of low signal-to-noise ratio of return light signals after multiplexing of a large number of equal-wavelength gratings and the like, so that the high-precision strain monitoring with high space density cannot be realized on a large-scale aircraft composite material.
In the prior art, the research on the ultra-weak reflection fiber bragg grating sensing technology based on the optical frequency domain reflection technology [ J ] optics report, 2015,35(8) ] is based on the OFDR technology, the multiplexing of 200 identical ultra-weak reflection fiber bragg gratings is realized on a single optical fiber, the grating interval is 20mm, and the detection effective length is only about 4 m.
In the prior art, a multiplexing technology of a railway safety monitoring sensor network based on FBGs (fiber Bragg gratings) is applied to information communication [ J ], 2019(6). A fiber bragg grating sensor network is constructed based on a conventional grating wavelength demodulation technology and combined with wavelength division multiplexing, time division multiplexing and space division multiplexing technologies, so that the sensing distance of kilometer magnitude is reached, but the strain spatial resolution is poor and is centimeter magnitude.
Disclosure of Invention
The utility model discloses an aim at overcomes prior art's is not enough, provides a large scale combined material space high density monitoring system that meets an emergency, realizes the monitoring of meeting an emergency of space high density on large scale combined material.
The technical solution of the utility model is as follows:
provided is a large-scale composite material strain space high-density monitoring system, which comprises: the device comprises an optical fiber sensor, a scanning laser, a test interference light path, a signal acquisition module and a signal processing system.
The optical fiber sensor is composed of an optical fiber with an equal-wavelength grating sub-array composite array, the length of the optical fiber is larger than 100m, the equal-wavelength grating sub-array composite array is formed by connecting n grating sub-arrays in series, the interval between every two grating sub-arrays is smaller than 1mm, the wavelengths of the grating sub-arrays are different, the grating sub-arrays are composed of gratings with the physical length smaller than 1cm, the space density smaller than 1mm and the total number larger than 1000 equal wavelengths, and the total number of the grating sub-arrays on the optical fiber is larger than 10.
The optical fiber sensor is composed of an optical fiber with a multi-wavelength grating sub-array composite array engraved thereon, the length of the optical fiber is more than 100m, the multi-wavelength grating sub-array composite array is formed by connecting n composite grating sub-arrays in series, the interval between every two composite grating sub-arrays is less than 1mm, the wavelengths of the composite grating sub-arrays are the same, and the composite grating sub-arrays are composed of gratings with different wavelengths, the physical length of which is less than 1cm, the spatial density of which is less than 1mm and the total number of which is more than 1000.
The scanning laser is a narrow linewidth wavelength linear scanning laser, and the wavelength range covers the wavelengths of all the gratings in the optical fiber sensor.
The test interference light path comprises a first 2 x 2 optical fiber coupler, a second 2 x 2 optical fiber coupler, a third 2 x 2 optical fiber coupler, an optical fiber coil, a first Faraday reflector, a second Faraday reflector and a third Faraday reflector, output light of the scanning laser is divided into two paths after passing through the first 2 x 2 optical fiber coupler, one path of the output light enters the second 2 x 2 optical fiber coupler and is divided into two paths for transmission, one path of the output light is reflected by the first Faraday reflector after passing through the optical fiber coil 7, the other path of the output light is reflected by the second Faraday reflector, and the two paths of the reflected light generate a reference interference signal at the output end of the second 2 x 2 optical fiber coupler; and the second path enters a third 2 x 2 optical fiber coupler and then is divided into two paths for transmission, one path of transmission light is reflected by a third Faraday reflector, the other path of transmission light enters an optical fiber sensor and is reflected by each grating on the optical fiber, and two paths of return light generate interference signals carrying strain information at the output end of the third 2 x 2 optical fiber coupler.
The signal acquisition module has the functions of wave division resolution, photoelectric conversion, analog signal acquisition and signal analog-to-digital conversion.
The signal processing system has the functions of scanning laser control, acquisition module control, grating sensing signal digital processing and strain information analysis.
The utility model relates to an above-mentioned novel large-scale combined material meets an emergency test step of high accuracy monitoring method includes:
step 1: laying the optical fiber engraved with the equal-wavelength grating subarray composite array or the multi-wavelength grating subarray composite array in an area needing strain testing of the composite material to be tested;
step 2: the output light of the scanning laser is divided into two paths after passing through the first 2 x 2 coupler, one path enters the second 2 x 2 optical fiber coupler and is divided into two paths for transmission, one path of light is reflected by the first Faraday reflector after passing through the optical fiber coil, the other path of light is reflected by the second Faraday reflector, and the two paths of reflected light generate a reference interference signal at the output end of the second 2 x 2 optical fiber coupler; and the second path enters a third 2 x 2 optical fiber coupler and then is divided into two paths for transmission, one path of transmission light is reflected by a third Faraday reflector, the other path of transmission light enters an optical fiber sensor and is reflected by each grating on the optical fiber, and two paths of return light generate interference signals carrying strain information at the output end of the third 2 x 2 optical fiber coupler.
And step 3: the two paths of interference signals form digital signals after passing through the signal acquisition module, and the digital signals are input into the signal processing system for corresponding signal processing.
The utility model has the advantages that: the utility model discloses a be carved with the optical fiber monitoring combined material's that has the compound array of equal wavelength grating subarray or be carved with the compound array of multi-wavelength grating subarray strain, the multiplexing quantity and the spatial distribution density of grating on the single fiber of increase, when guaranteeing optic fibre edge strain space high density, high accuracy monitoring, promoted optic fibre strain sensing's distance.
Drawings
Fig. 1 is an overall frame diagram of the strain space high-density monitoring system for large-scale composite material of the present invention.
Fig. 2 is a schematic structural diagram of a large-scale composite strain space high-density monitoring system according to an embodiment of the present invention.
Fig. 3 is a structural diagram of an optical fiber sensor of an equal-wavelength grating sub-array composite array according to an embodiment of the present invention.
Fig. 4 is a schematic view of an embodiment of the present invention, in which an optical fiber sensor is laid on a composite material, the optical fiber can be attached to the surface of the composite material or embedded inside the composite material.
Fig. 5 is a wavelength division multiplexing effect diagram of an optical fiber sensor based on an equal-wavelength grating sub-array composite array according to an embodiment of the present invention.
Fig. 6 is a flowchart illustrating the wavelength demodulation process of the optical fiber sensor based on the equal-wavelength grating sub-array composite array according to an embodiment of the present invention. Wherein a is an interference signal in a time domain, b is an interference signal in a frequency domain, c is a fiber bragg grating reflection position distribution diagram, d is a fiber bragg grating reflection position local distribution diagram, and e is a fiber bragg grating reflection spectrum.
Fig. 7 is a system diagram of the second embodiment of the present invention with additional sdm techniques.
Figure 8 example three the utility model discloses an optical fiber sensor structure chart of multi-wavelength grating array multiplex structure is adopted.
In the figure: the system comprises a signal processing system 1, a signal acquisition module 2, a test interference light path 3, a first 2 x 2 optical fiber coupler 4, a second 2 x 2 optical fiber coupler 5, a third 2 x 2 optical fiber coupler 6, an optical fiber coil 7, a first Faraday reflector 8, a second Faraday reflector 9, a third Faraday reflector 10, an optical fiber sensor 11 and a scanning laser 12.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail with reference to the accompanying drawings and embodiments. However, the following examples are only for explaining the present invention, and the scope of the present invention is not limited by the following examples.
Example one:
the utility model discloses a large scale combined material space high density monitoring system that meets an emergency, like figure 1, interfere light path 3, optical fiber sensor 11, signal acquisition module 2, signal processing system 1 including scanning laser 12, test.
The scanning laser is a narrow line wavelength wide range scanning laser, the coherence length is larger than 100m, the wavelength scanning range is larger than 40nm, and the wavelength range covers the wavelengths of all gratings in the optical fiber sensor.
The test interference light path comprises a first 2 x 2 optical fiber coupler 4, a second 2 x 2 optical fiber coupler 5, a third 2 x 2 optical fiber coupler 6, an optical fiber coil 7, a first Faraday reflector 8, a second Faraday reflector 9 and a third Faraday reflector 10, output light of the scanning laser 12 is divided into two paths after passing through the first 2 x 2 optical fiber coupler 4, one path enters the second 2 x 2 optical fiber coupler 5 and is divided into two paths for transmission, one path is reflected by the first Faraday reflector 8 after passing through the optical fiber coil 7, the other path is reflected by the second Faraday reflector 9, and the two paths of reflected light generate a reference interference signal at the output end of the second 2 x 2 optical fiber coupler 5; the second path enters a third 2 x 2 optical fiber coupler 6 and then is divided into two paths for transmission, one path of transmission light is reflected by a third Faraday reflector 10, the other path of transmission light enters an optical fiber sensor and is reflected by each grating on the optical fiber, and two paths of return light generate interference signals carrying strain information at the output end of the third 2 x 2 optical fiber coupler.
The first, second and third 2 x 2 fibre couplers are all 3dB, 50/50 fibre couplers.
The fiber coil 7 is a single-mode fiber with a length greater than 100 m.
As shown in fig. 3, the optical fiber sensor 11 is an optical fiber on which a grating sub-array composite array with equal wavelength is etched, the length of the optical fiber is greater than 100m, the grating sub-array composite array with equal wavelength is formed by connecting n grating sub-arrays in series, the interval between each two grating sub-arrays is less than 1mm, the wavelength of each grating sub-array is different, the grating sub-array is formed by gratings with physical length less than 1cm, spatial density less than 1mm and total number greater than 1000 equal wavelengths, and the total number of the grating sub-arrays on the optical fiber is greater than 10. Each grating sub-array on the fiber is marked as L1、L2、L3、L4....Ln，n>10, wavelength is respectively marked as lambda1、λ2、λ3、λ4....λn，n>10; each grating on each grating array is marked as Ln1、Ln2、Ln3、Ln4....Lnm，m>1000, wavelength is respectively marked as lambdan1、λn2、λn3、λn4....λnm。
The wavelength of the grating on the optical fiber sensor is linearly changed along with the strain of the grating.
The optical fiber sensor can be attached to the surface of the composite material or embedded in the composite material and is laid in an area needing strain testing on the composite material, and the optical fiber sensor needs to be straightened before being laid and is given a certain prestress, so that the optical fiber sensor can be well coupled into the optical fiber in a modified mode.
The signal acquisition module has the functions of photoelectric conversion, analog signal acquisition and 12-bit signal analog-to-digital conversion, and the sampling rate is greater than 10 MHz.
The signal processing system comprises the functions of scanning laser control, acquisition module control, grating sensing signal digital processing and strain information analysis.
The control of the scanning laser comprises setting a wavelength range of the laser, wherein the wavelength range covers the wavelengths of all grating sub-arrays in the optical fiber sensor, the scanning speed of the laser is set to be 40nm/s, and the output power of the laser is set to be 8 mW.
The control of the acquisition module comprises that the type of a sampling clock is set as an on-board clock, the sampling rate is set as 20MHz/s, the type of sampling trigger is set as rising edge trigger, the amount of sampling data is set as 1M, and the number of sampling channels is set as 1.
The grating sensing signal digital processing is shown in fig. 5 and 6, and includes (1) distinguishing interference signals returned by each grating sub-array from an optical frequency domain based on a wavelength division technique according to a wavelength range of each grating sub-array on the optical fiber sensor, and respectively performing subsequent signal processing. (2) And taking the output signal of the second 2 x 2 optical fiber coupler as a reference, and mapping the interference signal corresponding to each grating sub-array output by the third 2 x 2 optical fiber coupler from the time domain signal to the frequency domain. (3) And performing fast Fourier transform calculation on the interference signals of each grating sub-array on the frequency domain, and mapping the frequency domain signals to a space domain, thereby obtaining the exact positions of all the gratings on the optical fiber sensor. (4) And according to the position corresponding to each grating, performing inverse Fourier transform calculation on the spatial domain signal of each grating so as to obtain the reflection spectrum information of all the gratings on the optical fiber sensor.
And the strain information analysis comprises (1) recording initial wavelengths of all gratings after the optical fiber sensor is laid. (2) And the wavelength offset of all gratings along with the change of the strain field of the composite material during strain monitoring. (3) The grating wavelength shift is converted to a strain value. (4) And comparing the strain value of the composite material area where each grating is located according to the strain threshold, and giving warning information to the area with the change larger than the threshold.
Example two:
as shown in fig. 7, the "optical fiber engraved with equal-wavelength grating sub-array composite array" may be multiplexed by using space division technology on the basis of the first example. According to the number of the space division multiplexing optical fiber sensors, the number of corresponding test interferometers is increased in the interference test light path, and meanwhile, the signal acquisition module and the signal processing system are also provided with corresponding sampling channels and data processing capacity. The output light of the scanning laser can be split by the fourth 2 x 2 optical fiber coupler, one path of light enters the third 2 x 2 optical fiber coupler, the other path of light enters the fifth 2 x 2 optical fiber coupler, one path of transmission light is reflected by the fourth faraday reflector 13, and the other path of transmission light enters the second optical fiber sensor 14 and is reflected by each grating on the optical fiber.
Example three
In consideration of the diversity of the grating multiplexing forms on the optical fiber sensor, a multi-wavelength grating sub-array multiplexing structure shown in fig. 8 is also adopted, the multi-wavelength grating sub-array composite array is formed by connecting n composite grating sub-arrays in series, the interval between each two composite grating sub-arrays is less than 1mm, the wavelengths of the composite grating sub-arrays are the same, the composite grating sub-arrays are composed of gratings with physical lengths less than 1cm, spatial densities less than 1mm and total numbers greater than 1000 different wavelengths, and the total number of the grating sub-arrays on the optical fiber is greater than 10. L 'for each grating sub-array on the fiber'1、L’2、L’3、’L4....L’n，n>10; l 'is recorded as each raster on each raster array'n1、L’n2、L’n3、L’n4....L’nm，m>1000, wavelength is respectively marked as lambda1、λ2、λ3、λn4....λnm。
The above solutions can be expanded or modified in various ways, and are not described in detail, but belong to the patent.
Claims (6)
1. A large scale composite strain space high density monitoring system comprising: the optical fiber sensor is characterized by comprising an optical fiber with an equal-wavelength grating sub-array composite array, wherein the optical fiber is formed by connecting N grating sub-arrays in series, the interval between every two grating sub-arrays is smaller than 1mm, the wavelength of each grating sub-array is different, the grating sub-arrays are formed by gratings with physical length smaller than 1cm, space density smaller than 1mm and total number larger than 1000 equal wavelengths.
2. The large scale composite strain spatial high density monitoring system according to claim 1, wherein the scanning laser is a narrow linewidth wavelength linear scanning laser and the wavelength range covers the wavelengths of all gratings in the fiber optic sensor.
3. The large-scale composite material strain space high-density monitoring system according to claim 1, wherein the test interference optical path comprises a first 2 x 2 fiber coupler, a second 2 x 2 fiber coupler, a third 2 x 2 fiber coupler, a fiber coil, a first faraday reflector, a second faraday reflector and a third faraday reflector, output light of the scanning laser is divided into two paths after passing through the first 2 x 2 coupler, one path enters the second 2 x 2 fiber coupler and is divided into two paths for transmission, and reference interference signals are generated at an output end of the second 2 x 2 fiber coupler after being reflected by the first faraday reflector and the second faraday reflector respectively; and the other path enters a third 2 x 2 optical fiber coupler and then is divided into two paths for transmission, one path of transmission light is reflected by a third Faraday reflector, the other path of transmission light enters an optical fiber sensor and is reflected by each grating on the optical fiber, and two paths of return light generate interference signals carrying strain information at the output end of the third 2 x 2 optical fiber coupler.
4. A large scale composite strain space high density monitoring system comprising: scanning laser, test interference light path, signal acquisition module, signal processing system and fiber sensor, its characterized in that, fiber sensor constitute by a optic fibre that is carved with multi-wavelength grating subarray composite array, this fiber length is greater than 100m, multi-wavelength grating subarray composite array form by n composite grating subarrays establish ties, the interval between every composite grating subarray is less than 1mm, and the wavelength of every composite grating subarray is the same, composite grating subarray be less than 1cm by physical length, space density is less than 1mm, the total number is greater than 1000 different gratings of wavelength and constitutes, grating subarray total number is greater than 10 on the optic fibre.
5. The large scale composite strain spatial high density monitoring system according to claim 4, wherein the scanning laser is a narrow linewidth wavelength linear scanning laser and the wavelength range covers the wavelengths of all gratings in the fiber optic sensor.
6. The large-scale composite material strain space high-density monitoring system according to claim 4, wherein the test interference optical path comprises a first 2 x 2 fiber coupler, a second 2 x 2 fiber coupler, a third 2 x 2 fiber coupler, a fiber coil, a first faraday reflector, a second faraday reflector and a third faraday reflector, the output light of the scanning laser is divided into two paths after passing through the first 2 x 2 coupler, one path enters the second 2 x 2 fiber coupler and is divided into two paths for transmission, and the two paths are reflected by the first faraday reflector and the second faraday reflector respectively and then generate a reference interference signal at the output end of the second 2 x 2 fiber coupler; and the other path enters a third 2 x 2 optical fiber coupler and then is divided into two paths for transmission, one path of transmission light is reflected by a third Faraday reflector, the other path of transmission light enters an optical fiber sensor and is reflected by each grating on the optical fiber, and two paths of return light generate interference signals carrying strain information at the output end of the third 2 x 2 optical fiber coupler.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921583486.0U CN210464387U (en) | 2019-09-23 | 2019-09-23 | Large-scale composite material strain space high-density monitoring system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921583486.0U CN210464387U (en) | 2019-09-23 | 2019-09-23 | Large-scale composite material strain space high-density monitoring system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN210464387U true CN210464387U (en) | 2020-05-05 |
Family
ID=70434576
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921583486.0U Active CN210464387U (en) | 2019-09-23 | 2019-09-23 | Large-scale composite material strain space high-density monitoring system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN210464387U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110595376A (en) * | 2019-09-23 | 2019-12-20 | 中国科学院上海光学精密机械研究所 | Large-scale composite material strain space high-density monitoring method and system |
-
2019
- 2019-09-23 CN CN201921583486.0U patent/CN210464387U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110595376A (en) * | 2019-09-23 | 2019-12-20 | 中国科学院上海光学精密机械研究所 | Large-scale composite material strain space high-density monitoring method and system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5232982B2 (en) | OPTICAL FIBER SENSOR HAVING OPTICAL MARKING PART FOR LOCATION OF OPTICAL FIBER, MEASURING METHOD OF OPTICAL FIBER SENSOR, AND OPTICAL FIBER SENSOR DEVICE | |
| JP5413931B2 (en) | OPTICAL FIBER SENSOR HAVING OPTICAL MARKING PART FOR LOCATION OF OPTICAL FIBER, MEASURING METHOD OF OPTICAL FIBER SENSOR, AND OPTICAL FIBER SENSOR DEVICE | |
| Huang et al. | Demodulation of fiber Bragg grating sensor using cross-correlation algorithm | |
| CN102426198B (en) | Acoustic emission signal sensing system based on matching-type fiber Bragg grating (FBG) | |
| US10731969B2 (en) | In-line fiber sensing, noise cancellation and strain detection | |
| Hongo et al. | Applications of fiber Bragg grating sensors and high‐speed interrogation techniques | |
| CN104864911A (en) | High-speed demodulation device and method based on fiber fabry-perot cavity and fiber grating combined measurement | |
| CN114111909A (en) | Fiber Bragg grating temperature and stress dual-parameter integrated sensing and demodulating system based on diffraction grating | |
| CN112129332A (en) | Flexible multiplexing device of large-scale fiber grating sensor based on OFDR | |
| Hafizi et al. | Impact location determination on thin laminated composite plates using an NIR-FBG sensor system | |
| CN115597658A (en) | F-P cascade optical fiber sensor and method for measuring temperature and salt of seawater | |
| CN210464387U (en) | Large-scale composite material strain space high-density monitoring system | |
| JP3740500B2 (en) | OFDR multi-point strain measuring device | |
| WO2023069333A1 (en) | Few-mode rayleigh-based distributed fiber sensor for simultaneous temperature and strain sensing | |
| Gao et al. | A method on vibration positioning of Φ-OTDR system based on compressed sensing | |
| Wada et al. | Lateral load measurements based on a distributed sensing system of optical frequency-domain reflectometry using long-length fiber Bragg gratings | |
| CN107356275A (en) | A kind of method that spectral resolution is improved in optical frequency domain reflection-based optical fiber distributed sensing | |
| CN112649052A (en) | Ship body multi-parameter monitoring system and method based on all-fiber grating sensing network | |
| Guo et al. | Echelle diffractive grating based wavelength interrogator for potential aerospace applications | |
| CN110595376A (en) | Large-scale composite material strain space high-density monitoring method and system | |
| Fusiek et al. | Temperature-independent high-speed distributed voltage measurement using intensiometric FBG interrogation | |
| Kojima et al. | High-speed optical wavelength interrogator using a PLC-type optical filter for fiber Bragg grating sensors | |
| Pran et al. | Wavelength multiplexed fibre Bragg grating system for high-strain health monitoring applications | |
| Wen et al. | Fiber Bragg gratings sensing network with a bus chain typology structure | |
| Willshire et al. | Dynamic strain measurement using an extrinsic Fabry-Perot interferometric sensor and an arrayed waveguide grating device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |