CN101324445A - Distributed fiber optic white light interferometric sensor array based on tunable Fabry-Perot resonator - Google Patents

Abstract

The invention provides a distributed optical fiber white light interference sensor array based on an adjustable Fabry-Perot resonant cavity. It is composed of a duplex photoelectric device, an adjustable Fabry-Perot resonant cavity, a single-mode connecting optical fiber, and a sensor; an adjustable Fabry-Perot resonant cavity is composed of a scanning prism, a self-focusing lens, and a single-mode optical fiber connection with a partial reflection surface; the duplex The photoelectric device is composed of a wide-spectrum light source with a common base, an emitter, and a collector, and a photodetector through a beam-splitting prism; the light beam with a certain spectral width emitted by the light source directly reaches the resonator through the beam-splitting prism, and is absorbed by the left and right cavity surfaces of the resonator. After multiple reflections, the signal light is output from the right cavity surface; the signal light enters the sensor through the single-mode connection optical fiber, is respectively reflected by the left and right end surfaces of the sensor, returns along the original path, passes through the resonant cavity again, and is output from the left cavity surface , reaching the photodetector. The invention has a common optical path structure, good temperature stability, the simplest optical fiber optical path structure, low cost and strong practicability.

Description

Distributed fiber optic white light interferometric sensor array based on tunable Fabry-Perot resonator

(1) Technical field

The present invention relates to the field of optical fiber technology, in particular to a distributed optical fiber white light interference sensor array for interrogating multiple sensor signals based on an adjustable Fabry-Perot resonant cavity length.

(2) Background technology

Fiber-optic interferometers driven by low-coherence, broadband light sources such as light-emitting diodes (LEDs), superspontaneous emission sources (ASE) or multimode laser diodes are often referred to as white-light fiber interferometers. A typical optical fiber white light interferometer is shown in Figure 1. Its structure is to use optical fiber to build a Micheslon interferometer, and use a wide-spectrum light source LED or ASE to drive the interferometer to provide light energy for it, and detect white light interference through a detector. The stripes realize the measurement of the physical quantity to be measured. Its working principle is as follows. After the broadband light emitted by the broadband light source 11 enters the single-mode fiber, it is divided into two beams by the 3dB single-mode fiber 2×2 coupler 13, and one beam enters the single-mode fiber 14 used as the measuring arm. After being reflected by the optical reflection surface 15 at the rear end, it returns along the original path, passes through the single-mode optical fiber 14 and the coupler 13 to reach the photodetector 12, and this beam of light is called the measurement signal light; the light emitted by the light source 11 is shunted by the coupler 13 Another beam of light enters the single-mode connecting optical fiber 16 and the self-focusing lens 17 as the reference arm, and returns to the photodetector 12 along the same path after being reflected by the moving mirror 18. This beam of light is called the reference signal light . The measurement signal light and the reference signal light coherently superimpose on the surface of the detector. Since the coherence length of the broadband light source is very short, about several microns to tens of microns, only when the optical path difference between the reference signal light and the measurement signal is less than the light source When the coherence length is greater than the coherence length, coherent superposition will be generated, and a white light interference pattern will be output (see Figure 2).

As shown in Figure 2, the characteristic of white light interference fringes is that there is a main maximum value, called the central fringe, which corresponds to zero optical path difference, that is, when the optical path of the reference beam and the measurement beam are equal, it is called The reference beam and the measuring beam have an optical path matching relationship. By changing the delay amount of the fiber delay line and changing the optical path of the reference signal, the central interference fringe can be obtained. The position of the central fringe provides a reliable absolute position reference for the measurement. When the optical path of the measuring beam changes due to the influence of the external physical quantity to be measured, only the position of the white light interference fringe obtained by scanning the reference arm optical path changes. Gets the absolute value of the measured physical quantity. Compared with other fiber optic interferometers, in addition to the advantages of high sensitivity, intrinsic safety, and anti-electromagnetic field interference, the biggest feature is that it can perform absolute measurements on pressure, strain, and temperature. Therefore, the white light interferometric fiber optic interferometer is widely used in the measurement of physical quantities, mechanical quantities, environmental quantities, chemical quantities, and biomedical quantities.

In 2006, the applicant filed an invention patent application titled "Multiplexing Optical Fiber Interferometer and Its Nesting Construction Method" with the application number 200610151043.5, disclosing an all-fiber interferometer optical fiber that can construct sensor arrays and networks and its The implementation method solves the multiplexing problem of the optical fiber interferometer; the applicant also proposed an invention patent application named "Low Coherence Twisted Sagnac-like Optical Fiber Deformation Sensing Device" in 2007, and the application number is 200710072350.9, which discloses a A technical solution mainly used to solve the problem of anti-damage in the process of laying out the fiber optic sensor array. In the above public documents, especially when the white light interferometer is connected with a fiber optic sensor array, the optical paths of the local demodulation interferometer and the remote sensing interferometer are matched to realize interrogation and demodulation of the fiber optic sensor array. In this way, the sensing interferometer array can be completely passive, and the advantage is that the multiple interference signals output in the array are insensitive to the change of the length of the connecting fiber between the local demodulation interferometer and the sensor array, which enhances the stability of the measurement and reliability.

However, in the above interferometer structures based on space division multiplexing, most of the local demodulation interferometers use discrete interferometer structures such as Michelson interferometers and Mach-Zehnder interferometers. They usually have two independent optical transmission channels for optical path tuning and matching. However, because it does not have a common optical path structure, it is easily affected by environmental factors (such as temperature and vibration), resulting in inconsistent changes in the optical path of the two optical paths, which affects the demodulation of the sensor signal and reduces the signal resolution of the interferometer. Adjusting the sensitivity will reduce the measurement accuracy, and the long-term stability and reliability cannot be guaranteed; at the same time, the structure of the interferometer is also relatively complicated, which is not suitable for the practical application of the interferometer.

(3) Contents of the invention

The purpose of the present invention is to provide a distributed optical fiber with a common optical path structure, good temperature stability, simple optical path structure, low cost, strong practicability, and capable of sensing and detecting distributed deformation, strain, temperature, pressure and other physical quantities. White light interferometric sensor array.

The purpose of the present invention is achieved like this:

The distributed optical fiber white light interference sensor array of the present invention is a distributed optical fiber white light interference sensor array based on the adjustable Fabry-Perot resonant cavity length to realize interrogation, and consists of a duplex photoelectric device 1, an adjustable Fabry-Perot resonant cavity 2, a Mode connection optical fiber 3, sensor 4 constitutes; Adjustable Fabry-Perot resonant cavity 2 is composed of scanning prism 231, self-focusing lens 221, single-mode optical fiber connection with partial reflection surface 211; Duplex optoelectronic device 1 is composed of common base 113 , the wide-spectrum light source 111 of the emitter 112 and the collector 122 and the photodetector 121 are composed of a beam splitting prism 131; the light beam with a certain spectral width emitted by the light source 111 directly reaches the adjustable Fabry-Perot resonant cavity 2 through the beam splitting prism 131, and is After multiple reflections on the left and right cavity surfaces of the single-mode optical fiber with partial reflection surface 211 of the resonator, the signal light is output from the right cavity surface; the signal light enters the sensor 411 through the single-mode connecting optical fiber 3, and is respectively received by the left and right end surfaces of the sensor 411 After reflection, return along the original path, pass through the Fabry-Perot resonant cavity 2 again, and reach the photodetector 121 .

The sensor 4 is a serial sensor array composed of a group of optical fiber sensors 411 connected end to end.

The optical fiber sensor 411 is composed of an optical fiber section of any length perpendicular to the end face of the optical fiber with a certain reflectivity at both ends. It is a section of single-mode optical fiber that is intercepted according to actual measurement needs and is equipped with a ceramic ferrule 901 at both ends. After the end face is polished, an optical fiber sensor made of an optical fiber end face with a reflectivity perpendicular to the direction of light transmission greater than or equal to 1% is obtained.

The invention proposes a method for interrogating multiple sensor signals based on the adjustable Fabry-Perot resonant cavity length, and constructs a distributed optical fiber white light interference sensor array with the simplest structure on the single fiber line based on the method. This optical fiber white light interferometer has a common optical path structure and good temperature stability; it has the simplest optical path structure, low cost, strong practicability, and can sense and detect distributed deformation, strain, temperature, pressure and other physical quantities. The invention can be used for large-scale intelligent structure monitoring, and can also be used for multi-task sensing, multi-element sensing, local strain sensing and large-scale deformation sensing.

In the present invention, the broadband light source and the photodetector constitute a duplex optoelectronic device for transmitting and receiving, so that the reference light wave and the measurement light wave are transmitted in the same optical path, and the reference light wave reflected by the sensor is matched with the measurement light wave by tuning the length of the Fabry-Perot resonant cavity. The optical paths of the light waves are matched to obtain white light interference fringes, realizing the interrogation of multiple sensor signals.

This distributed optical fiber white light interferometric sensor array based on adjustable Fabry-Perot resonant cavity length to achieve interrogation is composed of an array composed of broadband light source, photodetector, adjustable Fabry-Perot resonant cavity, single-mode connecting optical fiber, and optical fiber sensor .

The wide-spectrum light source and the photodetector form a duplex photoelectric device for transmitting and receiving through a beam splitting prism.

The adjustable Fabry-Perot resonant cavity consists of a scanning prism, a self-focusing lens, and a single-mode optical fiber with a partial reflection surface to form an optical fiber delay line.

In the optical fiber Fabry-Perot resonant cavity device in the optical fiber interferometer, the cavity surface reflectivity of the resonant cavity can be arbitrarily selected between 1% and 99%.

In the optical fiber Fabry-Perot resonant cavity device in the optical fiber interferometer, the cavity length can be changed.

The array composed of optical fiber sensors is a serial array connected end to end by a series of single-mode optical fiber segments with different lengths.

The composition is based on the adjustable Fabry-Perot resonant cavity length to realize the optical fiber device of the distributed optical fiber white light interference sensor array, including broadband light source, photodetector, adjustable Fabry-Perot resonant cavity, single-mode connection optical fiber, optical fiber sensor Arrays, all work in a single-mode state.

Advantages and characteristics of the present invention are:

(1) The present invention adopts the adjustable Fabry-Perot resonator length to construct the distributed optical fiber white light interference sensor system, so that the demodulation interferometer and the optical fiber sensor array can be connected through an optical fiber, which greatly simplifies the optical path structure of the measurement system; at the same time The measurement optical path and the reference optical path realize a common optical path, which improves the anti-interference ability to the environment.

(2) Using adjustable Fabry-Perot resonant cavity length to construct a distributed optical fiber white light interferometric sensor system, without using complex time-division multiplexing or frequency-division multiplexing technology, only through continuous spatial optical path scanning, multiple The interrogation and measurement of a sensor signal is simple in technology and easy to implement.

(3) The distributed optical fiber white light interference sensor array constructed by the present invention can realize the arraying of optical fiber sensors, and the sensors do not affect each other during measurement. , multiple sensing, local strain sensing and large-scale deformation sensing capabilities.

(4) Using a duplex photoelectric device composed of a white light source and a photodetector, the measurement light path and the reference light path are multiplexed, which greatly simplifies the complexity of the system, reduces the test cost, and ensures the real-time performance of the test system. Measurement reliability.

(5) The optical fiber materials and devices used in the present invention are all standard optical fiber communication components, which are cheap, easy to obtain, and conducive to popularization.

(4) Description of drawings

Figure 1 is a schematic diagram of the structure of a typical white light interference Michelson interferometer.

Fig. 2 is a schematic diagram of a typical white light interference fringe signal.

Fig. 3 is a structural schematic diagram of the simplest optical fiber white light interference sensor for interrogation based on the adjustable Fabry-Perot resonant cavity length of the present invention.

Fig. 4 is a structural schematic diagram of the optical fiber sensor of the present invention.

Fig. 5 is a schematic structural diagram of an optical fiber delay line composed of an adjustable Fabry-Perot resonant cavity according to the present invention.

FIG. 6 is a schematic structural diagram of a distributed optical fiber white light interference sensor array for interrogation based on an adjustable Fabry-Perot resonant cavity length of the present invention.

Fig. 7 is a schematic diagram of a duplex optoelectronic device composed of a wide-spectrum light source and a photodetector according to the present invention.

Fig. 8 is the white light interference signal of the distributed optical fiber white light interference sensor array for interrogation based on the adjustable Fabry-Perot resonant cavity length of the present invention.

(5) Specific implementation methods

The present invention is described in more detail below in conjunction with accompanying drawing example:

Specific implementation mode one:

The basic principle of the present invention is based on the interference principle of low coherence, wide-spectrum light (white light) and the principle of space division multiplexing. The structure of the simplest optical fiber white light interference sensor array with adjustable Fabry-Perot resonant cavity length is shown in Figure 3, that is, only one sensor is connected to the sensor array. The outgoing light beam of the white light source 111 directly reaches the adjustable Fabry-Perot resonant cavity 2 through a dichroic prism 131, and after being repeatedly reflected by the left and right cavity surfaces of the resonator, the signal light is output from the right cavity surface; the signal light is respectively sent by the sensor 411 ( As shown in FIG. 4 ), the left and right end surfaces of the left and right sides return along the original path after reflection, and after passing through the Fabry-Perot resonant cavity 2 again, reach the photodetector 121 . In the above-mentioned series of optical signals with different optical paths, in the process of transmitting the optical signal from the light source to the sensor, and the sensor is reflected back to the detector, it only passes through the Fabry-Perot resonant cavity 2 once back and forth, and is detected The signal light reflected by the right end face of the sensor is called the measurement signal light; and in this process, it passes through twice when it comes and passes once when it returns or passes once when it comes and passes through the adjustable Fabry-Perot resonator twice when it comes back, and The light signal reflected by the left end face of the sensor 411 is called reference signal light. The measurement optical signal and the reference optical signal are coherently superimposed on the surface of the detector 121. Since the coherence length of the wide-spectrum low-coherence light source is very short, about several microns to tens of microns, only when the optical path difference between the reference signal and the measurement signal When it is smaller than the coherence length of the light source, coherent superposition will occur, and a white light interference pattern will be output.

$\mathrm{<span\; class="notranslate">\; I</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}\sqrt{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; \&gamma;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; |</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

In the formula: I ₁ and I ₂ are the signal intensities of the reference beam and the measuring beam, k is the wave number, x is the optical path difference between the two interference signals, Φ is the initial phase, and γ(x) is the autocorrelation function of the light source.

According to the above-mentioned definition of the optical path of the reference signal and the measurement signal, the so-called matching optical path of the reference light and the measurement light, specifically for the optical fiber measurement system in Figure 3, is the light accumulated by the reflection of the measurement signal on the left and right end faces of the sensor 4 The optical path is equal to the accumulated optical path length of the reference signal on the two cavity surfaces before and after the Fabry-Perot resonator 2, which is:

2nL+2nl＝2nL+2(nL ₀ +X) (2)

Among them, L is the length of the common optical fiber part, l is the length of the fiber sensor between the left and right reflective surfaces, n is the refractive index of the fiber core, nL ₀ is the Fabry-Perot resonator excluding the tuning length X The cavity length, X represents the tuning distance of the fiber delay line, as shown in Figure 6.

The interference fringes of the fiber optic interferometer based on the principle of white light interference only occur between a few microns and tens of microns near the optical path matching. Using this feature, multiplexing of sensors can be realized without using complex time division or frequency division multiplexing technology. As shown in FIG. 7 , the fiber optic sensors 411 are connected end to end to form a serial array 4 . The end face of each sensor 411 has a certain reflectivity. If the length of each sensor is greater than the coherence length of the light source, the interference fringes generated between the measurement light and the reference light are within their respective coherence lengths, and there is only a single white light interference signal, that is, the interference fringes do not interfere with each other and are independent; by Fabry -The tuning of the length of the Perot resonant cavity can realize spatial optical path scanning, distinguish multiple sensors, realize the query and interrogation of multiple external physical quantities, and realize distributed sensing very conveniently.

It can be seen that the basic construction idea of the distributed optical fiber white light interferometric sensor array based on the adjustable Fabry-Perot resonant cavity length to achieve interrogation is that the reference beam passes through the same optical path as the measuring beam after being delayed by the adjustable Fabry-Perot resonant cavity, and there is a one-to-one correspondence. Optical path matching makes the generated white light interference fringes independent and non-interfering with each other in the optical path scanning space. The matching of the reference beam can directly use the fiber delay line formed by the tunable Fabry-Perot resonant cavity to realize the scanning of the optical path.

Specific implementation mode two:

The scheme of distributed optical fiber white light interferometric sensor array with interrogation structure is realized by using adjustable Fabry-Perot resonant cavity length, as shown in Figure 7. It can be seen from the figure that the distributed optical fiber white light interference sensor array is composed of a duplex optoelectronic device 1 , an adjustable Fabry-Perot resonant cavity 2 , a single-mode connecting optical fiber 3 , and a serial sensor array 4 .

The optical fiber sensor 411 is composed of a section of optical fiber of any length perpendicular to the end face of the optical fiber with a certain reflectivity at both ends. The typical structure is shown in Figure 4. A section of single-mode optical fiber cut according to actual measurement needs is equipped with ceramic ferrules at both ends. 901. After the end face is polished, an optical fiber end face with a reflectivity perpendicular to the direction of transmitted light greater than or equal to 1% is obtained. The optical fiber sensor 411 can be connected to the sensor or the optical fiber through the ceramic sleeve 902, and the ceramic sleeve simultaneously protects the end face of the sensor. Several optical fiber sensors 411 are connected end to end to form a serial optical fiber sensor array 4 . In this embodiment, four fiber optic sensors X1 to X4 are connected end to end to form a sensing array. The average length of the fiber optic sensor is about 500mm, and the specific lengths are as follows: X1: 499.0mm, X2: 502.2mm, X3: 498.0mm, X4: 500.0mm.

As shown in FIG. 5 , the duplex optoelectronic device 1 is composed of a wide-spectrum light source 111 having a common base 113 , an emitter 112 , and a collector 122 , and a photodetector 121 passing through a dichroic prism 131 . Among them, the central wavelength of the broadband light source is 1300nm, the spectral width is 60nm, and the output power is 100 microwatts; the detector uses an InGaAs-based infrared detector, and its spectral response range is 1100nm-1700nm, and its responsivity is 0.9.

As shown in Figure 6, the adjustable Fabry-Perot resonant cavity 2 is composed of a scanning prism 231, a self-focusing lens 221, and a single-mode optical fiber with a partial reflection surface 211, wherein the single-mode optical fiber is an SMF-28 standard communication optical fiber, Its length is selected as 400 mm; the scanning prism 231 is a right-angled prism with a side length of 50.8 mm, and the moving range X of optical path scanning is 0-100 mm.

As shown in Fig. 7, the measurement arm of the interrogation-structured distributed optical fiber white light interferometric sensor array is connected with a serial optical fiber sensor array by using the adjustable Fabry-Perot resonant cavity length; the adjustable Fabry-Perot resonator is nested in the reference arm The cavity, whose function is to match the optical path of the reference beam and the measurement beam. Using the duplex photoelectric device 1 composed of the broadband light source 111 and the photodetector 121 through the dichroic prism 131, the reference arm and the measurement arm are combined into one. When the interferometer is working, the light from the broadband light source 111 in the duplex optoelectronic device passes through the adjustable Fabry-Perot resonant cavity 2 and then directly couples into the fiber sensor array 4, and is reflected by the right end face of each fiber sensor 411 in the serial array to form a A series of reflection measurement signal lights with different optical paths; after the light beams are reflected by the left end face of each fiber optic sensor 411 in the serial array, they are transmitted back to the dual sensor along the same path through the fiber delay line formed by the tuned Fabry-Perot resonant cavity. The detection end 121 in the industrial optoelectronic device forms a series of reference measurement signal lights with different optical paths; the optical path matching of the reference beam and the measurement beam and the acquisition of white light interference fringes are realized through the joint action of the two, when the tunable When the fiber delay line is adjusted to a certain position so that the total optical path of the Fabry-Perot resonator matches the nominal length of a certain sensor, the reflected signals from both ends of the sensor will produce white light interference fringes, as shown in Figure 8. And it can be seen from Figure 8 that the positions of the white light interference peaks have a one-to-one correspondence with the lengths of the sensors X1~X4. The spatial optical path scanning can be realized through the continuous tuning of the Fabry-Perot resonant cavity length, and multiple sensors can be distinguished. Inquiry and interrogation of multiple external physical quantities can thus be realized. When the sensor produces strain or displacement due to temperature, stress and other parameters, its optical path scanning position also changes accordingly, and the position value before and after the change is recorded. According to the conversion relationship, the sensor measurement of the parameter can be carried out.

Claims (8)

1. A distributed optical fiber white light interference sensor array based on an adjustable Fabry-Perot resonator, characterized in that it consists of a duplex photoelectric device (1), an adjustable Fabry-Perot resonator (2), and a single-mode connection optical fiber ( 3), the sensor (4) is formed; the adjustable Fabry-Perot resonant cavity (2) is composed of a scanning prism (231), a self-focusing lens (221), and a single-mode optical fiber connection with a partial reflection surface (211); duplex photoelectric The device (1) is composed of a wide-spectrum light source (111) with a common base (113), an emitter (112), and a collector (122), and a photodetector (121) through a beam splitting prism (131); the light source (111) The outgoing light beam with a certain spectral width directly reaches the adjustable Fabry-Perot resonator (2) through the beam splitter (131), and is reflected multiple times by the left and right cavity surfaces of the single-mode optical fiber with the partial reflection surface (211) of the resonator , the signal light is output from the right cavity surface; the signal light enters the sensor (411) through the single-mode connecting optical fiber (3), is respectively reflected by the left and right end faces of the sensor (411), returns along the original path, and passes through the Fabry-Perot resonant cavity again (2), after being output from the left cavity surface, it enters the duplex optoelectronic device (1), passes through the beam splitting prism (131) and then reaches the photodetector (121). 2. The distributed optical fiber white light interference sensor array based on the adjustable Fabry-Perot resonant cavity according to claim 1, characterized in that: the sensor (4) is composed of a group of optical fiber sensors (411) connected end to end serial sensor array. 3. The distributed optical fiber white light interference sensor array based on the adjustable Fabry-Perot resonant cavity according to claim 1 or 2, characterized in that: the optical fiber sensor (411) is a vertical sensor with a certain reflectivity at both ends. It is composed of a fiber segment of any length on the end face of the fiber. It is a single-mode fiber that is intercepted according to actual measurement needs and is equipped with a ceramic ferrule (901). After the end face is polished, the reflection perpendicular to the direction of the transmitted light is obtained. Optical fiber sensors made of optical fiber end faces with a rate greater than or equal to 1%. 4. The distributed optical fiber white light interference sensor array based on the adjustable Fabry-Perot resonant cavity according to claim 1 or 2, characterized in that: the reflectivity of the cavity surface in the Fabry-Perot resonant cavity is between 1%- Between 99%. 5. The distributed optical fiber white light interference sensor array based on the adjustable Fabry-Perot resonant cavity according to claim 3, characterized in that: the reflectivity of the cavity surface in the Fabry-Perot resonant cavity is between 1% and 99% between. 6. The distributed optical fiber white light interference sensor array based on adjustable Fabry-Perot resonant cavity according to claim 1 or 2, characterized in that: the cavity length of the Fabry-Perot resonant cavity is continuously variable. 7. The distributed optical fiber white light interference sensor array based on adjustable Fabry-Perot resonant cavity according to claim 3, characterized in that: the cavity length of the Fabry-Perot resonant cavity is continuously variable. 8. The distributed optical fiber white light interference sensor array based on the tunable Fabry-Perot resonant cavity according to claim 3, characterized in that: the sensors in the optical fiber sensing array have different lengths.

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