KR101915260B1 - Optical fiber sensor based strain measuring apparatus - Google Patents

Abstract

An optical fiber sensor-based strain measuring device is disclosed. The optical fiber sensor-based strain measuring apparatus according to an embodiment of the present invention includes a ring-shaped optical line, an optical amplifier provided in the optical line for amplifying light of a predetermined wavelength band, a circulator provided on the optical line for limiting the direction of light to one side A Fabry-Perot adjusting filter provided in the optical path and adjusting the optical path by varying the wavelength of the light, and an optical coupler provided in the optical path for branching and outputting the optical signal flowing in the optical path; A reflection wavelength of light which is coupled to the optical line to allow light to flow through the optical line to flow therethrough and reflects light of a predetermined wavelength that flows along the optical path adjusted by the Fabry-Perot adjustment filter by an optical line, A variable fiber grating array; And a strain measuring unit for analyzing the optical signal outputted through the optical coupler on the time axis and measuring a strain applied to the optical fiber grating array based on the amount of change of the peak of the optical signal on the time axis. According to the embodiment of the present invention, the safety of the structure can be detected in real time.

Description

TECHNICAL FIELD [0001] The present invention relates to an optical fiber sensor based strain measuring apparatus,

The present invention relates to an optical fiber sensor-based strain measuring device, and more particularly, to an optical fiber sensor-based strain measuring device for real-time monitoring of the safety of a structure by real-time measurement of strain using a wavelength-scanning laser and an optical fiber grating array.

There are a variety of techniques for monitoring the safety of large structures and structures. As an example, there is a technique of inserting a fiber Bragg grating into a structural structure to observe a wavelength change of light reflected from a fiber grating, thereby measuring strain due to vibration or cracks. However, the existing optical fiber grating measurement technique monitors the wavelength change of the light reflected from the optical fiber sensor, and the response characteristic of the wavelength range is very slow, and it is difficult to measure the wavelength change at high speed. As a result, it is difficult to measure the dynamic signal of the rapidly changing dynamic signal in real time, and the complicated signal processing is required for the structural safety monitoring.

An object of the present invention is to provide an optical fiber sensor-based strain measuring device capable of detecting the safety of a structure in real time.

The problems to be solved by the present invention are not limited to the above-mentioned problems. Other technical subjects not mentioned will be apparent to those skilled in the art from the description below.

An optical fiber sensor-based strain measuring apparatus according to one aspect of the present invention includes: a ring-shaped optical line; an optical amplifier provided in the optical line for amplifying light of a predetermined wavelength band; and an optical amplifier provided in the optical line, A Fabry-Perot adjusting filter provided in the optical line and adjusting the optical path by changing the wavelength of the light; and an optical coupler provided in the optical line for branching and outputting the optical signal flowing in the optical line, ; The optical fiber is coupled to the optical line so that light passing through the optical line is introduced into the optical line, and reflects light of a predetermined wavelength that flows along the optical line adjusted by the Fabry-Perot adjustment filter to the optical line, An optical fiber grating array whose light reflection wavelength is changed; And a strain measurement unit for analyzing the optical signal output through the optical coupler on a time axis and for measuring the strain applied to the optical fiber grating array based on a change amount on a time axis of a peak of the optical signal do.

The optical fiber grating array includes: an optical fiber coupled to the optical line to allow light to flow through the optical line; And a plurality of pairs of fiber gratings connected in series to the optical fiber.

Each of the pairs of optical fiber gratings may include a reference optical fiber grating provided such that the strain is not applied thereto, and a measurement optical fiber grating provided so that the strain acts.

The plurality of optical fiber grating pairs may be spaced apart from each other by a predetermined optical distance.

The optical fiber sensor-based strain measuring apparatus may further include a fiber-optic sensor-based strain measuring unit for calculating a fiber-optic grating pair based on the reflection index of the optical fiber, the linewidth of the Fabry-Perot adjustment filter, the frequency of light amplified by the optical amplifier, And an operation unit for calculating a maximum allowable interval of the display unit.

The reference optical fiber grating and the measurement optical fiber grating may be arranged to have optical distances equal to or less than the maximum allowable distance.

The strain measuring unit may include a peak detector for detecting a reference peak pulse of the optical signal generated by the light reflected by the reference fiber grating and a measured peak pulse of the optical signal generated by the light reflected by the measurement optical fiber grating, ; A peak difference calculator for measuring a time interval between the reference peak pulse and the measurement peak pulse in real time and measuring the intensity of a strain applied to the measurement optical fiber grating based on a time interval between the reference peak pulse and the measurement peak pulse; And a fast Fourier transform unit for fast Fourier transforming the time-varying data of the time interval between the reference peak pulse and the measured peak pulse to analyze a frequency component of a strain applied to the measurement optical fiber grating have.

The wavelength sweep laser may further include a frequency adjuster for adjusting a driving frequency of the Fabry-Perot adjusting filter so that light is sequentially reflected from the plurality of pairs of optical fiber gratings.

According to an embodiment of the present invention, an optical fiber sensor-based strain measuring device capable of detecting the safety of a structural structure in real time is provided.

The effects of the present invention are not limited to the effects described above. Unless stated, the effects will be apparent to those skilled in the art from the description and the accompanying drawings.

1 is a configuration diagram of an optical fiber sensor-based strain measuring apparatus according to an embodiment of the present invention.
2 is a configuration diagram of an analyzer constituting an optical fiber sensor-based strain measuring apparatus according to an embodiment of the present invention.
3 is a flowchart illustrating an operation performed by an analyzer constituting an optical fiber sensor-based strain measuring apparatus according to an embodiment of the present invention.
FIG. 4 is a graph showing the optical signal output from the wavelength-swept laser constituting the optical fiber sensor-based strain measuring device according to the embodiment of the present invention in a wavelength region and in a time domain.
FIG. 5 and FIG. 6 are graphs showing changes in wavelength of an optical signal output from a wavelength-swept laser constituting an optical fiber sensor-based strain measuring apparatus according to an embodiment of the present invention and a time interval between peaks measured in the time domain distance of the input signal.
7 is a view for explaining the operation of the peak detecting unit and the peak difference calculating unit of the optical fiber sensor-based strain measuring apparatus according to the embodiment of the present invention.
8 is a view for explaining the operation of the peak-difference calculating unit of the optical fiber sensor-based strain measuring apparatus according to the embodiment of the present invention.
9 is a view for explaining the operation of a fast Fourier transformer constituting an optical fiber sensor-based strain measuring apparatus according to an embodiment of the present invention.

Other advantages and features of the present invention and methods of achieving them will be apparent by referring to the embodiments described hereinafter in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and the present invention is only defined by the scope of the claims. Although not defined, all terms (including technical or scientific terms) used herein have the same meaning as commonly accepted by the generic art in the prior art to which this invention belongs. A general description of known configurations may be omitted so as not to obscure the gist of the present invention. In the drawings of the present invention, the same reference numerals are used as many as possible for the same or corresponding configurations. To facilitate understanding of the present invention, some configurations in the figures may be shown somewhat exaggerated or reduced.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises", "having", or "having" are intended to specify the presence of stated features, integers, steps, operations, components, Steps, operations, elements, parts, or combinations thereof, whether or not explicitly described or implied by the accompanying claims.

Used throughout this specification may refer to a hardware component such as, for example, software, FPGA or ASIC, as a unit for processing at least one function or operation. However, "to" is not meant to be limited to software or hardware. &Quot; to " may be configured to reside on an addressable storage medium and may be configured to play one or more processors.

As an example, the term '~' includes components such as software components, object-oriented software components, class components and task components, and processes, functions, attributes, procedures, Routines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functions provided by the components and components may be performed separately by a plurality of components and components, or may be integrated with other additional components.

The optical fiber sensor-based strain measuring apparatus according to an embodiment of the present invention analyzes the optical signal output from a wavelength sweep laser, an optical fiber grating array coupled to a wavelength sweep laser, and a wavelength sweep laser on a time axis, And a strain measuring unit for measuring a strain applied to the optical fiber grating array based on the measured strain.

When the dynamic strain is applied to the fiber grating array, the reflection wavelength of the fiber grating array changes dynamically. In this case, since the position of the pulse in the time axis changes according to the wavelength of the optical signal output from the wavelength swept laser, the optical signal output from the wavelength swept laser is analyzed on the time axis and the pulse position change on the time axis is observed. The strain applied to the structure can be measured.

It is very difficult to measure the wavelength change output by the optical fiber sensor at a high speed due to the slow response speed of the wavelength region, but the change of the peak position in the time domain can be detected in real time. Therefore, according to the embodiment of the present invention, it is possible to measure information such as the intensity of a dynamically changing strain, frequency characteristics, etc. at a high speed, and to monitor the safety of the structure in real time.

1 is a configuration diagram of an optical fiber sensor-based strain measuring apparatus according to an embodiment of the present invention. Referring to FIG. 1, an optical fiber sensor-based strain measuring apparatus 100 according to an embodiment of the present invention includes a wavelength sweep laser 120, an optical fiber grating array 140, and a strain measuring unit 160.

The wavelength swept laser 120 is configured to vary the wavelength of light according to the light reflected from the optical fiber grating array 140 at a high speed.

In one embodiment, the wavelength sweep laser 120 includes an optical path 121, an optical amplifier 122, a circulator 123, an optical path adjustment unit 124, a delay line 125 , Polarization controllers 126a and 126b, isolators 127a and 127b, and an optical coupler 128. [

The light path 121 may be provided in the form of a ring. The optical path 121 may be provided as an optical fiber.

The optical amplifier 122 is provided as a gain medium that functions as a laser light source for emitting light to the optical path 121 and amplifies light of a predetermined wavelength band in the optical path 121 .

In one embodiment, the optical amplifier 122 may be provided as a semiconductor optical amplifier, but is not limited thereto.

The circulator 123 restricts the direction of light flowing in the light path 121 to one side (clockwise or counterclockwise).

The light path adjusting unit 124 is provided for adjusting the light path by varying the wavelength of light. In one embodiment, the optical path adjustment unit 124 may include a Fabry-Perot Tunable Filter 124a and a frequency adjustment unit 124b.

The Fabry-Perot adjustment filter 124a adjusts the optical path of light by adjusting the wavelength of light according to the frequency input by the frequency adjuster 124b.

The delay line 125 may be provided with a single mode optical fiber and may be provided with a predetermined long length (e.g., several Km).

Polarization controllers 126a and 126b regulate the polarization of the light traveling in the light path 121. [

The isolators 127a and 127b transmit the light in one direction in the light path 121 and block the light in the opposite direction.

The optical coupler 128 splits a part of the optical signal flowing in the optical path 121 and outputs the split optical signal to the strain measuring unit 160.

The optical fiber grating array 140 is coupled to the optical line 121 to allow light to flow through the optical line 121. The optical fiber grating array 140 reflects light of a specific wavelength flowing along the optical path to the optical path 121, and transmits the remaining wavelengths.

In the optical fiber grating array 140, the reflection wavelength of the light reflected by the optical path 121 is changed according to an applied strain.

In one embodiment, the optical fiber grating array 140 includes an optical fiber 141 coupled to the optical line 121 to allow light to flow into the optical line 121, a single mode optical fiber 142, 146, 147, and an optical fiber 141 And a plurality of pairs of optical fiber gratings 143, 144, and 145 connected in series.

The plurality of pairs of optical fiber gratings 143, 144, and 145 may be provided to be spaced apart from each other by a predetermined distance in the optical distance. For this, the single mode optical fibers 142, 146, 147 may be provided with optical distances of several meters to several hundred meters.

Each of the pairs of optical fiber gratings 143, 144 and 145 may include reference optical gratings FBG2, FBG4 and FBG6 which are not subjected to strain and measurement gratings FBG1, FBG3 and FBG5, have.

In one embodiment, the measurement fiber gratings FBG1, FBG3, FBG5 may be inserted into the structural structure such that the strain applied to the structural structure is well transmitted. The reference fiber gratings FBG2, FBG4, FBG6 may be disposed outside the structural structure so that the strain applied to the structural structure is transmitted.

The reference optical fiber gratings FBG2, FBG4 and FBG6 of the optical fiber grating pairs 143, 144 and 145 and the measurement optical fiber gratings FBG1, FBG3 and FBG5 may be provided to have optical distances equal to or less than a predetermined distance (maximum allowable distance). Here, the optical distance may be a distance measured along a path through which the light travels, including the length of the single mode optical fiber.

In one embodiment, an operation unit (not shown) for calculating the maximum allowable interval may be provided. The arithmetic unit may include a refractive index of the optical fiber 141, an instantaneous linewidth of the Fabry-Perot adjustment filter 124a, a frequency of the light amplified by the optical amplifier 122, The maximum allowable interval between the reference optical fiber gratings FBG2, FBG4, and FBG6 and the measured optical fiber gratings FBG1, FBG3, and FBG5 can be calculated based on the wavelength band width of the reference optical fiber gratings FBG2, FBG4, and FBG6.

In one embodiment, the maximum allowable spacing between the reference fiber gratings FBG2, FBG4, FBG6 and the measured fiber gratings FBG1, FBG3, FBG5 can be calculated according to Equation 1 below.

[Formula 1]

The maximum allowable interval between the reference fiber gratings FBG2, FBG4 and FBG6 and the measured fiber gratings FBG1, FBG3 and FBG5, c is the speed of light, N is the reflection index of the optical fiber 141, f is the frequency of the light amplified by the optical amplifier 122, and [Delta] [lambda] _TF is the 3 dB bandwidth of the wavelength sweep laser 120. [ π is a factor to compensate for non-linearity.

For example, the optical distance between the reference optical fiber gratings FBG2, FBG4, and FBG6 and the measurement optical fiber gratings FBG1, FBG3, and FBG5 may be determined within a range of several to several tens of cm, according to Equation 1 above.

For example, when a frequency of 41.370 kHz is input from the frequency adjusting unit 124b to the Fabry-Perot adjusting filter 124a, the first optical fiber grating pair 143 transmits the light of the corresponding reflection wavelength to the optical path 121 So that the strain applied to the first optical fiber grating pair 143 can be measured at this time.

As another example, when a frequency of 41.230 kHz is input from the frequency adjusting section 124b to the Fabry-Perot adjusting filter 124a, the second optical fiber grating pair 144 outputs the light of the corresponding reflection wavelength to the optical path 121 And at this time, the strain applied to the second pair of optical fiber gratings 144 can be measured.

As another example, when a frequency of 41.045 kHz is input from the frequency adjusting unit 124b to the Fabry-Perot adjusting filter 124a, the third optical fiber grating pair 145 transmits light of a corresponding reflection wavelength to the optical path 121, And at this time, the strain applied to the third pair of optical fiber gratings 145 can be measured.

Thus, the frequency of the light in the optical fiber grating array 140 can be adjusted by adjusting the wavelength of the light by adjusting the frequency inputted to the Fabry-Perot adjusting filter 124a by the frequency adjusting unit 124b . Therefore, it is possible to determine by which of the optical fiber grating pairs 143, 144, and 145 the light is to be reflected by the frequency adjusting unit 124b, and the position where the strain is applied can also be specified.

In one embodiment, the frequency adjustment unit 124b may continuously and sequentially adjust the driving frequency of the Fabry-Perot adjustment filter 124a so that light is sequentially reflected from the plurality of optical fiber grating pairs 143, 144, and 145 . Therefore, it is possible to monitor the structural safety in real time over the entire section where the optical fiber grating array 140 is installed.

The strain measuring unit 160 analyzes the optical signal output through the optical coupler 128 on the time axis and measures the strain applied to the fiber grating array based on the amount of change of the peak of the optical signal on the time axis.

In one embodiment, the strain measuring unit 160 detects an optical signal branched from the optical line 121 through the optical fiber line 161, the optical detector 162, and the optical coupler 128, board 163 and an analysis device 164.

The optical signal branched from the optical line 121 through the optical coupler 128 is transmitted through the optical fiber line 161 and is detected by a photo detector 162. The optical signal corresponding to the optical signal Is provided to the data collection board 163.

The analyzer 164 receives electrical signals collected at a predetermined sampling rate from the data collection board 163 and measures the strain applied to the fiber grating array 140.

2 is a configuration diagram of an analyzer constituting an optical fiber sensor-based strain measuring apparatus according to an embodiment of the present invention. 2, the analyzer 164 includes a peak detector 1642, a comparator 1644, a peak difference calculator 1646, and a fast Fourier transformer 1648.

3 is a flowchart illustrating an operation performed by an analyzer constituting an optical fiber sensor-based strain measuring apparatus according to an embodiment of the present invention. 1 to 3, the signal transmitted from the data acquisition board 163 is read to generate an input signal (S1, S2).

FIG. 4 is a graph showing the optical signal output from the wavelength-swept laser constituting the optical fiber sensor-based strain measuring device according to the embodiment of the present invention in a wavelength region and in a time domain.

4A and 4D are measurement results for the first optical fiber grating pair 143 and FIGS. 4B and 4E are measurement results for the second optical fiber grating pair 144, 4C and 4F are measurement results for the third pair of optical fiber gratings 145. FIG.

(D), (e), and (f) of FIG. 4 are graphs showing the input signals in the analyzer 164 along the time axis (S3).

The position (time) of the pulse of the input signal on the time axis changes in accordance with the wavelength of the light of the optical signal output from the wavelength sweep laser 120. [ It can be seen that the reflection wavelengths of the first to third optical fiber grating pairs 143, 144, and 145 are designed to be different from each other, and the generation position (time) of the peak appears different in the time domain as shown in FIG.

Since the light is reflected from the reference fiber grating and the measurement fiber grating that constitute the optical fiber grating pair, when the reflection wavelengths of the reference optical fiber grating and the measurement optical fiber grating are different, two pulses appear on the time axis in the input signal.

FIG. 5 and FIG. 6 are graphs showing changes in wavelength of an optical signal output from a wavelength-swept laser constituting an optical fiber sensor-based strain measuring apparatus according to an embodiment of the present invention and a time interval between peaks measured in the time domain distance of the input signal.

5 and 6, since the wavelength of the optical signal output from the wavelength-swept laser constituting the optical fiber sensor-based strain measuring device and the time interval between the peaks measured in the time domain exhibit linearity, It can be seen that the wavelength change can be measured accurately by measuring the time interval between peaks.

7 is a view for explaining the operation of the peak detecting unit and the peak difference calculating unit included in the optical fiber sensor based strain measuring apparatus according to the embodiment of the present invention. The peak detector 1642 detects the reference peak pulse P2 of the optical signal generated by the light reflected from the reference fiber gratings FBG2, FBG4 and FBG6 and the light reflected from the measurement optical fiber gratings FBG1, FBG3 and FBG5 (Step S4).

The comparator 1644 compares the peak pulses P1 and P2 with a threshold to recognize the peak pulse as a peak when the intensity of the peak pulse is equal to or higher than the threshold and does not recognize the peak as a peak when the intensity is lower than the threshold, S6).

8 is a view for explaining the operation of the peak-difference calculating unit of the optical fiber sensor-based strain measuring apparatus according to the embodiment of the present invention. Referring to FIGS. 1 to 3, 7 and 8, the peak-difference calculator 1646 real-time-measures the time interval? T between the reference peak pulse P2 and the measured peak pulse P1 (S7).

8 is a graph showing the time interval? T between the reference peak pulse P2 and the measured peak pulse P1 calculated on the time axis by the peak difference calculator 1646 (S8). The peak-difference calculator 1646 measures the intensity of the strain applied to the measurement optical fiber gratings FBG1, FBG3, FBG5 based on the variation (amplitude) of the measured time interval? T as shown in Fig.

9 is a view for explaining the operation of a fast Fourier transformer constituting an optical fiber sensor-based strain measuring apparatus according to an embodiment of the present invention. The fast Fourier transform unit 1648 performs Fast Fourier Transform on the time-varying data of the time interval t between the reference peak pulse and the measured peak pulse to calculate a strain Fs (FBG1, FBG3, FBG5) (S9, S10).

As described above, the optical fiber sensor-based strain measuring apparatus according to the embodiment of the present invention measures the pulse position change on the time axis instead of the wavelength range response characteristic of the optical sensor signal that varies dynamically according to the strain, Variable strains can be measured in real time.

In the time domain, high-speed photodetectors and oscilloscopes can be used to monitor the interval between two pulse peaks at high speed in real time. Therefore, in the present invention, since the response speed is much faster than that of the wavelength region analysis, complicated signal processing is not required, and the computation amount is small, the dynamic change of the structure can be monitored in real time without delay time.

The optical fiber sensor-based strain measuring device of the present invention can be applied to inspect structural safety by monitoring a dynamic strain change due to vibrations or cracks in real time by inserting an optical fiber grating into a large building or structure. In particular, it is possible to monitor in real time without signal processing delay for dynamic change rapidly changing in kHz level, so that danger can be detected early and the countermeasure can be taken quickly to prevent accidents.

The strain measurement method performed in accordance with an embodiment of the present invention can be implemented in a general-purpose digital computer that can be created as a program that can be executed on a computer, for example, and operates the program using a computer-readable recording medium . The computer readable recording medium may be a volatile memory such as SRAM (Static RAM), DRAM (Dynamic RAM), SDRAM (Synchronous DRAM), ROM (Read Only Memory), PROM (Programmable ROM), EPROM (Electrically Programmable ROM) Non-volatile memory such as EEPROM (Electrically Erasable and Programmable ROM), flash memory device, Phase-change RAM (PRAM), Magnetic RAM (MRAM), Resistive RAM (RRAM), Ferroelectric RAM But are not limited to, optical storage media such as CD ROMs, DVDs, and the like.

It is to be understood that the above-described embodiments are provided to facilitate understanding of the present invention, and do not limit the scope of the present invention, and it is to be understood that various modified embodiments are also within the scope of the present invention. It is to be understood that the technical scope of the present invention should be determined by the technical idea of the claims and the technical scope of protection of the present invention is not limited to the literary description of the claims, To the invention of the invention.

100: Fiber-optic sensor-based strain measuring device
120: Wavelength scanning laser
121: Light ray
122: optical amplifier
123: Circulator
124:
124a: Petri-Perot adjustment filter
124b:
125: delay line
126a, 126b: polarization controller
127a, 127b: isolator
128: Optocoupler
140: Fiber Bragg Grating Array
141: Optical fiber
142,146,147: Single mode fiber
143,144,145: Fiber grating pair
160: Strain measuring unit
161: fiber optic line
162: Photodetector
163: Data collection board
164: Analyzer
1642:
1644:
1646: Peak difference calculation section
1648: Fast Fourier transform unit
FBG1, FBG3, FBG5: Measuring fiber grating
FBG2, FBG4, FBG6: Reference fiber grating

Claims (5)

An optical amplifier provided in the optical line and amplifying light in a predetermined wavelength band; a circulator provided in the optical line to limit the direction of light to one side; and a light source provided in the optical line, A Fabry-Perot adjustment filter for adjusting an optical path, and an optical coupler provided in the optical path for branching and outputting an optical signal flowing through the optical path;
The optical fiber is coupled to the optical line so that light passing through the optical line is introduced into the optical line, and reflects light of a predetermined wavelength that flows along the optical line adjusted by the Fabry-Perot adjustment filter to the optical line, An optical fiber grating array whose light reflection wavelength is changed; And
And a strain measurement unit for analyzing the optical signal output through the optical coupler on a time axis and measuring the strain applied to the optical fiber grating array based on a change amount on a time axis of a peak of the optical signal ,
The optical fiber grating array includes:
An optical fiber coupled to the optical line to allow light to flow through the optical line; And
And a plurality of pairs of optical fiber gratings connected in series to the optical fiber,
Wherein each pair of optical fiber gratings includes a reference fiber grating provided so that the strain is not applied and a measurement optical fiber grating provided so that the strain can be applied. delete The method according to claim 1,
The plurality of pairs of optical fiber gratings are spaced apart from each other by a predetermined optical distance,
Calculating a maximum permissible interval of the pair of optical fiber gratings based on a reflection index of the optical fiber, a line width of the Fabry-Perot adjustment filter, a frequency of light amplified by the optical amplifier, and a wavelength band width of the wavelength- ; ≪ / RTI >
Wherein the reference optical fiber grating and the measurement optical fiber grating are disposed so as to have optical distances equal to or less than the maximum allowable distance. The method according to claim 1,
The strain measuring unit includes:
A peak detector for detecting a reference peak pulse of the optical signal generated by the light reflected by the reference fiber grating and a measured peak pulse of the optical signal generated by the light reflected by the measurement optical fiber grating;
A peak difference calculator for measuring a time interval between the reference peak pulse and the measurement peak pulse in real time and measuring the intensity of a strain applied to the measurement optical fiber grating based on a time interval between the reference peak pulse and the measurement peak pulse; And
And a fast Fourier transformer for analyzing a frequency component of a strain applied to the measurement optical fiber grating by fast Fourier transforming time-varying data of a time interval between the reference peak pulse and the measurement peak pulse, Based strain measuring device. The method according to claim 1,
The wavelength-
The optical fiber sensor-based strain measuring device according to claim 1, further comprising a frequency adjusting unit adjusting a driving frequency of the Fabry-Perot adjusting filter so that light is sequentially reflected from the plurality of pairs of optical fiber gratings.

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