An edge filter, quasi-distributed FBG sensor demodulation system and method

Abstract

The present invention discloses a demodulation method for a quasi-distributed FBG sensor based on a novel edge filter, belonging to the technical field of FBG sensor demodulation. The demodulation system includes a pulse laser, an optical fiber coupler, an optical fiber connector, a single-mode optical fiber No. 1, an edge filter, a single-mode optical fiber No. 2, a fiber Bragg grating No. 1, a fiber Bragg grating No. 2, a photodetector, a voltage amplifier, an A / D converter, and a data collector. A novel edge filter is used for demodulation of the fiber Bragg grating sensor. By changing the structural parameters of the edge filter, it can adapt to fiber Bragg gratings with different central wavelengths. The reflected light of the FBG array is converted from a wavelength signal to an energy signal after passing through the edge filter, thereby realizing FBG array sensor demodulation. Ultimately, fast demodulation of the FBG with a wide range, low noise, high sensitivity, high stability, and low cost is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of FBG sensor demodulation, and in particular to a demodulation method of a quasi-distributed FBG sensor based on a novel edge filter. Background Art

[0002] In recent years, fiber Bragg gratings (FBGs) have been widely used in fields such as temperature, strain, and humidity sensing, chemical gas measurement, trace element detection, and structural health monitoring. Compared with traditional electronic sensors, FBG sensors have advantages such as small size, light weight, immunity to electromagnetic interference, and ease of forming distributed sensor networks. Most reported FBG sensor analysis techniques use optical spectrum analyzers (OSAs) to extract characteristic wavelengths or bandwidths representing external physical quantities. OSAs have high measurement accuracy, but due to limited resolution, large size, and high cost, they face significant challenges in engineering applications. Therefore, the development of a new, low-cost FBG sensor demodulation scheme is crucial.

[0003] Several demodulation methods for fiber Bragg grating (FBG) sensors have been widely proposed. These methods are typically based on fiber Sagnac loops, self-phase modulation, microwave photons, and wavelength-swept tunable lasers. The sensitivity and accuracy of these demodulation methods often rely on other optoelectronic components in the system, such as erbium-doped fiber amplifiers (EDFAs) and electro-optical intensity modulators (EOMs), which inevitably introduce unwanted system noise. Furthermore, complex system designs can increase costs. Consequently, these demodulation schemes may be incompatible across different FBG sensor networks, presenting limitations in engineering applications. Therefore, developing a low-dependence, low-noise, and low-cost FBG sensor demodulation method and system has become an urgent challenge. Summary of the Invention

[0004] This invention aims to address the aforementioned challenges of FBG demodulation technology by proposing a demodulation method for quasi-distributed FBG sensors based on a novel edge filter. Here, we propose a novel edge filter consisting of a cascaded dispersion-compensating fiber (DCF) and a coreless fiber (NCF) structure between two single-mode fibers (SMFs). This filter utilizes its linear filtering properties to convert the fiber Bragg grating (FBG) wavelength signal into an optical power signal, which is then demodulated by measuring the optical power offset. By varying the structural parameters of the edge filter, it can accommodate fiber Bragg gratings with varying central wavelengths, enabling wide-range FBG demodulation. This edge filter is used as the foundation for a FBG array demodulation system, enabling rapid, low-noise, high-sensitivity, high-stability, and low-cost FBG demodulation.

[0005] To achieve the above objectives, the present invention adopts the following technical solutions:

[0006] An edge filter includes a single-mode optical fiber No. 3, a dispersion-compensating optical fiber, a coreless optical fiber, and a single-mode optical fiber No. 4, which are connected in sequence; the dispersion-compensating optical fiber has a length of 8 mm and a cladding diameter of 110 μm; the coreless optical fiber has a length of 2 mm; the output end of the single-mode optical fiber No. 3 is coaxially fused with the input end of the dispersion-compensating optical fiber, the output end of the dispersion-compensating optical fiber is coaxially fused with the input end of the coreless optical fiber, and the output end of the coreless optical fiber is coaxially fused with the input end of the single-mode optical fiber No. 4 5-4.

[0007] An edge filter-based FBG array sensing and demodulation system includes a connected pulse laser, a fiber coupler, a fiber connector, a single-mode fiber No. 1, an edge filter, a single-mode fiber No. 2, a fiber Bragg grating No. 1, a fiber Bragg grating No. 2, a photodetector, a voltage amplifier, an A / D converter, and a data collector, wherein:

[0008] The fiber coupler includes three ports, P1, P2, and P3. The P1 end is connected to the output end of the pulse laser, and the P2 and P3 ends are respectively connected to the input end of the photodetector and the input end of the fiber front-end connector; the output end of the fiber connector is connected to the first end of the single-mode fiber No. 1, the input end and the output end of the edge filter are respectively connected to the tail end of the single-mode fiber No. 1 and the first section of the single-mode fiber No. 2, and the first section and the tail end of the fiber Bragg grating No. 1 are respectively connected to the tail end of the single-mode fiber No. 2 and the first section of the fiber Bragg grating No. 2; the input and output ends of the voltage amplifier are respectively connected to the output end of the photodetector and the input end of the A / D converter, and the output end of the A / D converter is connected to the input end of the data collector.

[0009] Preferably, the pulse power of the pulse laser is 10 mW, the pulse width is 10 ns, the loss measurement accuracy is 0.01 dB, and the group refractive index range is 1.400000 -1.699999, wherein the power of 10 mW is relatively large in the light source and is used to compensate for the loss of pulse light during the transmission process of the entire system. The setting of the 10 ns pulse width is to improve the spatial resolution of the demodulation point. The narrower the pulse width, the better the spatial resolution.

[0010] Preferably, the optical fiber coupler has a splitting ratio of 1:1, the lengths of single-mode optical fiber No. 1 and single-mode optical fiber No. 2 are both 1000m, and the attenuation coefficient is 0.18dB / km, which ensures balanced splitting and better data processing of the electrical signal after photoelectric conversion.

[0011] Preferably, the splitting ratio of the optical fiber coupler is 1:1, the length of the single-mode optical fiber No. 1 and the single-mode optical fiber No. 2 are both 1000m, and the attenuation coefficient is 0.18dB / km.

[0012] Preferably, the reflectivity of the fiber Bragg grating No. 1 and the fiber Bragg grating No. 2 are both 10%, the 3dB bandwidth is both 0.08nm, the period is both 0.528μm, and the grating region length is both 15mm.

[0013] Preferably, the photodetector is a balanced photodetector, which converts the collected light signal into an electrical signal, amplifies the voltage through a voltage amplifier, converts it into a digital signal through an A / D converter, and finally processes and displays it by a data collector.

[0014] Preferably, the optical paths of the pulse laser, fiber coupler, fiber connector, single-mode fiber No. 1, edge filter, single-mode fiber No. 2, fiber Bragg grating No. 1, fiber Bragg grating No. 2, photodetector, voltage amplifier, A / D converter, and data collector are all connected by arc discharge fusion through single-mode optical fiber.

[0015] A demodulation method for a quasi-distributed FBG sensor based on an edge filter is disclosed. The pulsed light emitted by a pulsed laser passes through a fiber coupler, a fiber connector, a single-mode fiber No. 1, an edge filter, and a single-mode fiber No. 2 to reach fiber Bragg gratings No. 1 and No. 2. Light that meets the Bragg grating wavelength conditions is reflected. The reflected light of fiber Bragg gratings No. 1 and No. 2 is converted from a wavelength signal to an energy signal after passing through the edge filter. The converted energy signal is transmitted to a photodetector through a fiber coupler, undergoes voltage amplification, A / D conversion, and data acquisition, and finally restores the energy signal filtered by the edge filter, thereby realizing FBG array sensing demodulation.

[0016] The beneficial effects of the present invention are:

[0017] 1. By varying the structural parameters of the edge filter, the present invention can adapt to fiber Bragg gratings (FBGs) with different central wavelengths, thereby expanding its application in diverse fiber Bragg grating (FBG) sensor networks. This method exhibits high sensitivity and stability and enables simultaneous demodulation of multiple FBG parameters. The proposed edge filter exhibits 10-20 times the sensitivity of conventional edge filters in FBG demodulation. Furthermore, the edge filter is low-cost, simple to manufacture, and manufacturable. These advantages make it superior to conventional edge filters in engineering applications. It can effectively address related engineering problems, particularly in the fields of fiber Bragg grating (FBG) sensing systems and optical device design.

[0018] 2. The edge filter of the present invention, with a dispersion-compensating fiber length of 8 mm and a coreless fiber length of 2 mm, is suitable for demodulating FBGs within a certain range of central wavelengths. The lengths of the DCF and NCF can be adjusted to accommodate demodulation of FBGs within different central wavelength ranges. This adjustable structural parameter expands the demodulation range and provides a solution for demodulating different FBG sensor networks. The demodulation sensitivity and accuracy of this edge filter are fundamentally determined by the transmission characteristics of the edge filter itself, with minimal dependence on the system. This edge filter, when used for FBG demodulation, offers advantages such as high sensitivity, adjustable structural parameters, low cost, and the ability to independently achieve multi-point / multi-parameter demodulation. Furthermore, this edge filter is simple to manufacture and can be produced. These advantages are superior to traditional edge filters in engineering applications. It can effectively address related engineering problems, particularly in the fields of fiber Bragg grating sensing systems and optical device design. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the demodulation system structure of a quasi-distributed FBG sensor based on a novel edge filter of the present invention;

[0020] Figure 2 This is a connection diagram of a new edge filter introduced in the present invention.

[0021] Among them: 1: pulse laser, 2: fiber coupler, 3: fiber connector, 4: fiber No. 1, 5: edge filter, 6: single-mode fiber No. 2, 7: fiber Bragg grating No. 1, 8: fiber Bragg grating No. 2, 9: photodetector, 10: voltage amplifier, 11: A / D converter, 12: data collector; 5-1: single-mode fiber No. 3, 5-2: dispersion-compensating fiber, 5-3: coreless fiber, 5-4: single-mode fiber No. 4. DETAILED DESCRIPTION

[0022] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0023] Dispersion-compensating fiber (DCF) is a new type of fiber with large negative dispersion. It is designed for existing G652 standard single-mode fiber systems using WDM / EDFA technology. Because the dispersion of G652 standard fiber at a wavelength of 1.55μm is not zero, but positive (17-20) ps / (nm·km), and has a positive dispersion slope, it is necessary to connect these fibers with dispersion-compensating fibers with negative dispersion to compensate for the dispersion. This ensures that the total dispersion of the entire fiber line is close to zero, thus enabling high-speed, high-capacity, and long-distance communications.

[0024] The explanation of "single-mode fiber" in academic literature: Generally, when v is less than 2.405, there is only one wave crest passing through the optical fiber, so it is called single-mode fiber. Its core is very thin, about 8 to 10 microns, and the mode dispersion is very small. The main factors affecting the width of the optical fiber transmission band are various dispersions, and mode dispersion is the most important. The dispersion of single-mode fiber is small, so it can transmit light over a long distance with a very wide frequency band.

[0025] Single-mode fiber has a core diameter of 10 microns, allowing for single-mode beam transmission and eliminating bandwidth and modal dispersion limitations. However, due to the small core diameter of single-mode fiber, beam transmission is difficult to control, requiring extremely expensive lasers as light sources. The main limitation of single-mode optical cables is material dispersion. Single-mode optical cables primarily utilize lasers to achieve high bandwidths. Since LEDs emit a large number of light sources with different bandwidths, material dispersion requirements are very important.

[0026] Compared to multimode fiber, single-mode fiber has a much thinner core diameter, only 8 to 10 μm. Because it transmits only a single mode, there is no intermodal dispersion, resulting in low total dispersion and a wide bandwidth. Single-mode fiber operates in the 1.3 to 1.6 μm wavelength range. By properly designing the fiber's refractive index profile and selecting a cladding material with a purity seven times greater than the core, single-mode fiber achieves both minimal loss and minimal dispersion in this wavelength range.

[0027] Single-mode optical fiber is used in long-distance, high-capacity optical fiber communication systems, optical fiber local area networks and various optical fiber sensors.

[0028] This embodiment provides a demodulation method for a quasi-distributed FBG sensor based on a novel edge filter, comprising a pulse laser 1, a fiber coupler 2, a fiber connector 3, a single-mode fiber No. 1 4, an edge filter 5, a single-mode fiber No. 2 6, a fiber Bragg grating No. 1 7, a fiber Bragg grating No. 2 8, a photodetector 9, a voltage amplifier 10, an A / D converter 11, and a data collector 12, wherein:

[0029] The optical fiber coupler (2) includes three ports P1, P2, and P3. The P1 end is connected to the output end of the pulse laser (1), and the P2 and P3 ends are respectively connected to the input end of the photodetector (9) and the input end of the optical fiber front-end connector (3).

[0030] The output end of the optical fiber connector (3) is connected to the head end of the single-mode optical fiber No. 1 (4), the input end and the output end of the edge filter (5) are respectively connected to the tail end of the single-mode optical fiber No. 1 (4) and the head end of the single-mode optical fiber No. 2 (6), and the head end and the tail end of the fiber Bragg grating No. 1 (7) are respectively connected to the tail end of the single-mode optical fiber No. 2 (6) and the head end of the fiber Bragg grating No. 2 (8).

[0031] The input and output ends of the voltage amplifier (10) are respectively connected to the output end of the photodetector (9) and the input end of the A / D converter (11), and the output end of the A / D converter (11) is connected to the input end of the data collector (12).

[0032] A demodulation method for a quasi-distributed FBG sensor based on a novel edge filter is characterized by: a pulse laser (1) having a pulse power of 10 mW, a pulse width of 10 ns, a loss measurement accuracy of 0.01 dB, and a group refractive index range of 1.400000-1.699999. The 10 mW power is relatively large in the light source and is used to compensate for the loss of the pulse light during the transmission process of the entire system. The 10 ns pulse width is set to improve the spatial resolution of the demodulation point. The narrower the pulse width, the better the spatial resolution.

[0033] A demodulation method for a quasi-distributed FBG sensor based on a novel edge filter is proposed. The optical fiber coupler has a 1:1 splitting ratio, single-mode optical fiber No. 1 and single-mode optical fiber No. 2 are both 1000m long, and the attenuation coefficient is 0.18dB / km. This method ensures balanced splitting and better data processing of the electrical signal after photoelectric conversion.

[0034] A demodulation method for a quasi-distributed FBG sensor based on a novel edge filter. Edge filter 5 is a novel edge filter designed by us and comprises single-mode fiber No. 3 5-1, dispersion-compensating fiber 5-2, coreless fiber 5-3, and single-mode fiber No. 4 5-4. Dispersion-compensating fiber 5-2 is 8 mm long and has a cladding diameter of 110 μm. Coreless fiber 5-3 is 2 mm long. The output end of single-mode fiber No. 3 5-1 is coaxially spliced ​​to the input end of dispersion-compensating fiber 5-2, the output end of dispersion-compensating fiber 5-2 is coaxially spliced ​​to the input end of coreless fiber 5-3, and the output end of coreless fiber 5-3 is coaxially spliced ​​to the input end of single-mode fiber No. 4 5-4.

[0035] A demodulation method for a quasi-distributed FBG sensor based on a novel edge filter is proposed. The fiber Bragg grating No. 1 7 and the fiber Bragg grating No. 2 8 both have a reflectivity of 10%, a 3dB bandwidth of 0.08nm, a period of 0.528μm, and a grating length of 15mm.

[0036] A demodulation method for a quasi-distributed FBG sensor based on a novel edge filter is proposed. The photodetector 9 is a balanced photodetector that converts the collected optical signal into an electrical signal, which is then amplified by a voltage amplifier 10 and converted into a digital signal by an A / D converter 11. The digital signal is finally processed and displayed by a data collector 12.

[0037] A demodulation method for a quasi-distributed FBG sensor based on a novel edge filter is disclosed. The optical connections of all devices are made by arc discharge fusion connection through single-mode optical fibers.

[0038] A demodulation method for a quasi-distributed FBG sensor based on a novel edge filter is disclosed. The pulsed light emitted by a pulsed laser passes through a fiber coupler, a fiber connector, single-mode fiber No. 1, an edge filter, and single-mode fiber No. 2 to reach fiber Bragg gratings No. 1 and No. 2. Light that meets the Bragg grating wavelength requirements is reflected. The reflected light from fiber Bragg gratings No. 1 and No. 2 is converted from a wavelength signal to an energy signal after passing through the edge filter. The converted energy signal is then transmitted to a photodetector through a fiber coupler. After voltage amplification, A / D conversion, and data acquisition, the energy signal filtered by the edge filter is finally restored, thereby achieving FBG array sensing demodulation.

[0039] A demodulation method for quasi-distributed FBG sensors based on a novel edge filter employs a novel edge filter for demodulation of fiber Bragg grating (FBG) sensors. By varying the structural parameters of the edge filter, it can accommodate fiber Bragg gratings (FBGs) with different central wavelengths, thereby expanding its application in diverse fiber Bragg grating (FBG) sensor networks. This method exhibits high sensitivity and stability and enables simultaneous demodulation of multiple FBG parameters. The proposed edge filter exhibits 10-20 times the sensitivity of traditional edge filters for FBG demodulation. Furthermore, the edge filter is low-cost, simple to fabricate, and manufacturable. These advantages make it superior to traditional edge filters in engineering applications. The method can effectively address related engineering problems, particularly in the design of fiber Bragg grating (FBG) sensing systems and optical devices.

[0040] Measuring principle of the present invention

[0041] The transfer function of the proposed edge filter in the linear region can be expressed as:

[0042] P out =(C1λ i +C2)P in (1)

[0043] where λ i is the wavelength of the light injected into SDNS. out represents the output light intensity of the edge filter; C1 and C2 are the slope windows of the SDNS spectrum, corresponding to the descending slope area and the ascending slope area, respectively. in Represents the power of the input light. The FBG reflection center wavelength can be expressed as:

[0044] λ B =2n eff Λ (2)

[0045] where λ Bis the FBG reflection wavelength, n eff is the effective refractive index of the optical fiber core, and Λ is the refractive index modulation period.

[0046] The change of FBG center wavelength caused by external interference such as temperature and strain can be expressed as:

[0047] Δλ=(1-p e )ε+(α Λ +α n )ΔT (3)

[0048] Where Δλ is the wavelength change caused by external disturbance; ε and ΔT are strain and temperature changes respectively. e is the effective strain optical constant; α Λ and α n are the thermal expansion coefficient and thermo-optical coefficient of the optical fiber, respectively.

[0049] Combining equations (1) and (3), we can obtain the following equation:

[0050] ΔP=P in [C1(1-p e )ε+C1(α Λ +α n )ΔT] (4)

[0051] As can be seen from the above formula, the reflected light power detected by the OTDR will change linearly with the temperature and strain applied to the FBG. Therefore, changes in the FBG due to temperature and strain can be detected by detecting changes in the reflected light power, rather than detecting changes in the demodulation wavelength.

[0052] The transfer characteristics of the proposed edge filter can be expressed as:

[0053]

[0054] Where, I co and are the light intensities of the fundamental mode and the m-order cladding mode, L is the effective interference length (the sum of the DCF and NCF lengths), λ is the wavelength of the incident light, and Δ neff is the effective refractive index difference between the core mode and the m-order cladding mode.

Claims

1. An FBG array sensor demodulation system based on an edge filter, characterized by: The invention comprises a connected pulse laser (1), a fiber coupler (2), a fiber connector (3), a single-mode fiber No. 1 (4), an edge filter (5), a single-mode fiber No. 2 (6), a fiber Bragg grating No. 1 (7), a fiber Bragg grating No. 2 (8), a photodetector (9), a voltage amplifier (10), an A / D converter (11), and a data acquisition device (12), wherein: The fiber coupler (2) comprises three ports, P1, P2 and P3, wherein the P1 end is connected to the output end of the pulse laser (1), and the P2 and P3 ends are respectively connected to the input end of the photodetector (9) and the input end of the fiber front connector (3); the output end of the fiber connector (3) is connected to the head end of the single-mode fiber No. 1 (4), the input end and the output end of the edge filter (5) are respectively connected to the tail end of the single-mode fiber No. 1 (4) and the head section of the single-mode fiber No. 2 (6), and the head section and the tail end of the fiber Bragg grating No. 1 (7) are respectively connected to the tail end of the single-mode fiber No. 2 (6) and the head section of the fiber Bragg grating No. 2 (8); the input and output ends of the voltage amplifier (10) are respectively connected to the output end of the photodetector (9) and the input end of the A / D converter (11), and the output end of the A / D converter (11) is connected to the input end of the data collector (12); The edge filter (5) includes a single-mode optical fiber No. 3 (5-1), a dispersion-compensating optical fiber (5-2), a coreless optical fiber (5-3), and a single-mode optical fiber No. 4 (5-4) connected in sequence; the output end of the single-mode optical fiber No. 3 (5-1) is coaxially fused with the input end of the dispersion-compensating optical fiber (5-2), the output end of the dispersion-compensating optical fiber (5-2) is coaxially fused with the input end of the coreless optical fiber (5-3), and the output end of the coreless optical fiber (5-3) is coaxially fused with the input end of the single-mode optical fiber No. 4 (5-4); the length of the dispersion-compensating optical fiber (5-2) is 8 mm, and the cladding diameter is 110 μm; the length of the coreless optical fiber (5-3) is 2 mm; The transfer function of the edge filter in the linear region is expressed as: P out =(C1λ i +C2)P in (1) where λ i is the wavelength of light injected into SDNS; P out represents the output light intensity of the edge filter; C1 and C2 are the slope windows of the SDNS spectrum, corresponding to the descending slope area and the ascending slope area, respectively. in Indicates the power of input light; The FBG reflection center wavelength is expressed as: l B =2n eff L (2) where λ B is the FBG reflection wavelength, n eff is the effective refractive index of the optical fiber core, Λ is the refractive index modulation period; The change of FBG center wavelength caused by external interference is expressed as: Δλ=(1-p e )e+(a Λ +a n )ΔT (3) where Δλ is the wavelength change caused by external disturbance; ε and ΔT are the strain and temperature changes respectively; p e is the effective strain optical constant; α Λ and α n are the thermal expansion coefficient and thermo-optical coefficient of the optical fiber, respectively; Combining equations (1) and (3), we can obtain the following equation: ΔP=P in [C1(1-p e )ε+C1(α Λ +a n )ΔT] (4) The transfer characteristics of the proposed edge filter are expressed as: Where, I co and are the light intensities of the fundamental mode and the m-order cladding mode, respectively; L is the effective interference length, i.e., the sum of the DCF and NCF lengths; λ is the wavelength of the incident light; Δ neff is the effective refractive index difference between the core mode and the m-order cladding mode.

2. The FBG array sensing demodulation system based on an edge filter according to claim 1, characterized in that: The pulse laser (1) has a pulse power of 10 mW, a pulse width of 10 ns, a loss measurement accuracy of 0.01 dB, and a group refractive index range of 1.400000-1.699999.

3. The FBG array sensing demodulation system based on edge filter according to claim 1, characterized in that: The optical fiber coupler has a splitting ratio of 1:1, the lengths of single-mode optical fiber No. 1 and single-mode optical fiber No. 2 are both 1000 m, and the attenuation coefficient is 0.18 dB / km.

4. The FBG array sensing demodulation system based on an edge filter according to claim 1, characterized in that: The optical fiber coupler has a splitting ratio of 1:1, the lengths of single-mode optical fiber No. 1 and single-mode optical fiber No. 2 are both 1000 m, and the attenuation coefficient is 0.18 dB / km.

5. The FBG array sensing demodulation system based on edge filter according to claim 1, characterized in that: The fiber Bragg grating No. 1 (7) and the fiber Bragg grating No. 2 (8) both have a reflectivity of 10%, a 3dB bandwidth of 0.08nm, a period of 0.528μm, and a grating region length of 15mm.

6. The FBG array sensing demodulation system based on edge filter according to claim 1, characterized in that: The photodetector (9) is a balanced photodetector that converts the collected optical signal into an electrical signal, which is then amplified by a voltage amplifier (10), converted into a digital signal by an A / D converter (11), and finally processed and displayed by a data collector (12).

7. The FBG array sensing demodulation system based on edge filter according to claim 1, characterized in that: The optical paths of the pulse laser (1), the optical fiber coupler (2), the optical fiber connector (3), the single-mode optical fiber No. 1 (4), the edge filter (5), the single-mode optical fiber No. 2 (6), the fiber Bragg grating No. 1 (7), the fiber Bragg grating No. 2 (8), the photodetector (9), the voltage amplifier (10), the A / D converter (11), and the data collector (12) are all connected by arc discharge fusion connection through the single-mode optical fiber.

8. A demodulation method for an edge filter-based FBG array sensor demodulation system according to claim 1, characterized in that: The pulsed light emitted by the pulse laser passes through a fiber coupler-fiber connector-single-mode fiber No. 1-edge filter-single-mode fiber No. 2 to reach fiber Bragg gratings No. 1 and No.

2. The light that meets the Bragg grating wavelength conditions will be reflected. The reflected light of fiber Bragg gratings No. 1 and No. 2 is converted from a wavelength signal to an energy signal after passing through the edge filter. The converted energy signal is transmitted to a photodetector through a fiber coupler, and after voltage amplification, A / D conversion, and data acquisition, the energy signal filtered by the edge filter is finally restored, thereby realizing FBG array sensing demodulation.

Images