Fiber grating demodulation device and modulator module thereof

Abstract

This invention discloses a fiber Bragg grating demodulation device and its modulator module, relating to the field of fiber optic sensors, for achieving low-cost and miniaturized design of fiber Bragg grating demodulation. In this invention, a broadband optical signal emitted from a light source enters the fiber Bragg grating sensor via a coupler. Each fiber Bragg grating sensor sequentially reflects its own wavelength optical signal, which then passes through the coupler and enters an on-chip Fourier spectrometer. Under the voltage applied by a voltage-driven module, the on-chip Fourier spectrometer modulates the wavelength optical signal reflected by the fiber Bragg grating sensor and performs photoelectric conversion on the modulated signal. The converted electrical signal is then transmitted to a signal acquisition and processing module for wavelength optical signal reconstruction, thereby achieving demodulation of the wavelength optical signal reflected by the fiber Bragg grating sensor. This invention enables low-cost and miniaturized design of fiber Bragg grating demodulation and allows for flexible expansion of the number of demodulation channels.

Description

Technical Field

[0001] This invention relates to the field of fiber optic sensor technology, and in particular to a fiber optic grating demodulation device and its modulator module. Background Technology

[0002] Fiber Bragg Grating (FBG) demodulation technology is crucial for high-precision extraction of wavelength-coded information. Currently known FBG demodulation techniques include spectral detection, tunable laser sources, and tunable FP filtering demodulation, all of which are widely used in fiber optic demodulation products.

[0003] The aforementioned fiber Bragg grating demodulation technologies each have their own characteristics, but due to limitations in their technical solutions, they cannot achieve miniaturization and lightweight design, and their costs are all relatively high, making them unsuitable for applications where there are strict limitations on the cost and size of fiber optic sensor demodulation systems. Summary of the Invention

[0004] The purpose of this invention is to provide a fiber Bragg grating demodulation device and its modulator module to address all or part of the problems mentioned above, thereby achieving a low-cost and miniaturized design for fiber Bragg grating sensing demodulation.

[0005] The technical solution adopted in this invention is as follows: In a first aspect, the present invention provides a fiber Bragg grating demodulation apparatus, comprising: At least one set of spectrometer modules; each spectrometer module includes a light source, a coupler, and an on-chip Fourier spectrometer; each set of spectrometer modules is used to connect to one fiber Bragg grating sensor; Each group of spectrometer modules is connected to a voltage drive module and a signal acquisition and processing module, respectively. Under the voltage applied by the voltage drive module, each group of spectrometer modules modulates the wavelength light signal reflected by the fiber optic grating sensor, performs photoelectric conversion on the modulated signal, and transmits the converted electrical signal to the signal acquisition and processing module for wavelength light signal reconstruction.

[0006] Optionally, the on-chip Fourier spectrometer includes a modulator module and a photodetector; the modulator module is connected to the coupler, the voltage drive module, and the photodetector respectively, so as to modulate the wavelength optical signal transmitted by the coupler under the voltage applied by the voltage drive module; the photodetector is used to perform photoelectric conversion on the modulated signal; the photodetector is connected to the signal acquisition and processing module.

[0007] Optionally, the modulator module includes an input waveguide, an output waveguide, a 2×2 waveguide coupler, electrodes, a first waveguide transmission arm, and a second waveguide transmission arm; the input waveguide, output waveguide, first waveguide transmission arm, and second waveguide transmission arm are respectively connected to the 2×2 waveguide coupler; the first waveguide transmission arm and the second waveguide transmission arm are axially symmetrical to each other; the electrodes are connected to the voltage driving module to apply the voltage applied by the voltage driving module to the first waveguide transmission arm and the second waveguide transmission arm.

[0008] Optionally, both the first waveguide transmission arm and the second waveguide transmission arm are asymmetric Y-waveguide structures, and each free end has reflection capability.

[0009] Optionally, the first waveguide transmission arm includes a first asymmetric Y-waveguide, a second asymmetric Y-waveguide, and a first waveguide ring; the first asymmetric Y-waveguide is connected to the 2×2 waveguide coupler, the first waveguide ring, and the second asymmetric Y-waveguide; the free end of the second asymmetric Y-waveguide forms a ring structure; the second waveguide transmission arm includes a third asymmetric Y-waveguide, a fourth asymmetric Y-waveguide, and a second waveguide ring; the third asymmetric Y-waveguide is connected to the 2×2 waveguide coupler, the second waveguide ring, and the fourth asymmetric Y-waveguide; the free end of the fourth asymmetric Y-waveguide forms a ring structure.

[0010] Optionally, each asymmetric Y-waveguide includes a main waveguide, a narrow waveguide, and a wide waveguide; the narrow waveguide and the wide waveguide are respectively connected to the main waveguide.

[0011] Optionally, in the first waveguide transmission arm, the first asymmetric Y-waveguide and the second asymmetric Y-waveguide are rotationally symmetric; in the second waveguide transmission arm, the third asymmetric Y-waveguide and the fourth asymmetric Y-waveguide are rotationally symmetric.

[0012] Optionally, the wide waveguide of the first asymmetric Y-waveguide is connected to the 2×2 waveguide coupler, and the narrow waveguide is connected to the first waveguide loop; the main waveguide of the first asymmetric Y-waveguide is connected to the main waveguide of the second asymmetric Y-waveguide; the wide and narrow waveguides of the second asymmetric Y-waveguide are connected end-to-end; the wide waveguide of the third asymmetric Y-waveguide is connected to the 2×2 waveguide coupler, and the narrow waveguide is connected to the second waveguide loop; the main waveguide of the third asymmetric Y-waveguide is connected to the main waveguide of the fourth asymmetric Y-waveguide; the wide and narrow waveguides of the fourth asymmetric Y-waveguide are connected end-to-end.

[0013] Furthermore, the signal acquisition and processing module reconstructs the electrical signal according to the following configuration: The signal acquisition and processing module uses a Fourier transform algorithm to reconstruct the wavelength optical signal from the electrical signal.

[0014] In a second aspect, the present invention also provides an intermediate product of the designed fiber Bragg grating demodulation device, namely a modulator module for the fiber Bragg grating demodulation device. The modulator module includes an input waveguide, an output waveguide, a 2×2 waveguide coupler, electrodes, a first waveguide transmission arm, and a second waveguide transmission arm. The input waveguide, output waveguide, first waveguide transmission arm, and second waveguide transmission arm are respectively connected to the 2×2 waveguide coupler. The first waveguide transmission arm and the second waveguide transmission arm are axially symmetrical to each other. The electrodes are connected to the voltage driving module to apply the voltage applied by the voltage driving module to the first waveguide transmission arm and the second waveguide transmission arm.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: The fiber Bragg grating demodulation device provided by this invention involves a broadband optical signal emitted from a light source entering a fiber Bragg grating sensor via a coupler. Each fiber Bragg grating sensor sequentially reflects its own wavelength optical signal, which then enters an on-chip Fourier transform spectrometer after passing through the coupler. A signal acquisition and processing module controls a voltage drive module on the modulator module of the on-chip Fourier transform spectrometer to emit a triangular wave drive voltage for periodic scanning. The modulated optical signal is converted into an electrical signal by a photodetector (PD) and acquired by a signal acquisition and processing module. The acquired signal is processed by a Fourier transform algorithm configured in the signal acquisition and processing module to obtain a spectral signal related to the electrical signal output by the photodetector (PD). This electrical signal corresponds to the wavelength optical signal entering the on-chip Fourier transform spectrometer, allowing the reconstruction of the fiber Bragg grating sensor's spectrum. A peak-finding algorithm is then used to obtain the wavelength of each fiber Bragg grating sensor, ultimately achieving demodulation of the fiber Bragg grating sensor. The fiber Bragg grating demodulation device provided by this invention achieves low-cost, miniaturized fiber Bragg grating demodulation and can be flexibly expanded into a multi-channel demodulation device. Attached Figure Description

[0016] The present invention will be described by way of example and with reference to the accompanying drawings, wherein: Figure 1 This is a structural diagram of a single-channel fiber Bragg grating demodulation device in one embodiment.

[0017] Figure 2 This is a structural diagram of a modulator module in one implementation.

[0018] Figure 3 This is a structural diagram of an asymmetric Y-waveguide in one implementation.

[0019] Figure 4 This is a schematic diagram illustrating the evolution of asymmetric Y-waveguide transmission modes.

[0020] Figure 5This is a structural diagram of a multi-channel fiber Bragg grating demodulation device in one embodiment. Detailed Implementation

[0021] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0022] Any feature disclosed in this specification (including any appended claims and abstract) may be replaced by other equivalent or similar features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0023] Known fiber Bragg grating demodulation techniques include spectral detection, tunable laser source method, and tunable FP filter demodulation method.

[0024] The fiber optic demodulation module based on spectral detection uses a diffraction grating to disperse the spectrum before projecting it onto a CCD for wavelength acquisition. This solution employs a broadband light source, but the demodulation module requires optical switches to expand its capabilities for multi-channel acquisition, resulting in low real-time performance for multi-channel data.

[0025] The tunable laser source method uses a semiconductor swept-frequency laser as the light source. The swept-frequency range is divided into n equal-wavelength intervals for scanning. Simultaneously, a trigger signal is emitted during the sweep to drive photoelectric signal acquisition. One scan yields the spectral signal across the entire range, and the sensor wavelength is calculated from this signal. This technical solution allows for simultaneous scanning of the light source across multiple channels, resulting in high speed, small size, and high real-time performance.

[0026] The tunable FP filter demodulation method uses a tunable filter and a semiconductor optical amplifier to form a ring cavity, driving the filter to generate a wavelength-tunable light source, thereby achieving sensor signal scanning. The scanning wavelength corresponds to the filter driving voltage, and wavelength restoration is achieved by comparing the voltage with the acquired photoelectric signal. This technical solution offers a wide demodulation range and high precision.

[0027] However, although the aforementioned fiber Bragg grating demodulation technologies each have their advantages, they are all relatively large in size, making it impossible to achieve miniaturization and lightweight design; in addition, their construction costs are all high, making them unsuitable for large-scale applications.

[0028] With the development of industries such as robotics, new energy, and consumer electronics, fiber optic sensors, as a sensor technology with electromagnetic immunity, high sensitivity, fast response, and small size, have found increasingly diverse applications. However, the large-scale application of fiber optic sensors places high demands on the construction cost and size of demodulation systems, making large-volume, high-cost solutions unsuitable for their mass production.

[0029] In view of the above situation, this application proposes a miniaturized and low-cost fiber optic grating demodulation device, which aims to achieve miniaturized and low-cost design of fiber optic demodulation products, and facilitate the low-cost, mass production and application of fiber optic sensors.

[0030] like Figure 1 As shown, the fiber optic grating demodulation device includes a light source, a coupler, an on-chip Fourier spectrometer, a voltage drive module, and a signal acquisition and processing module.

[0031] In one optional embodiment, the on-chip Fourier spectrometer includes a modulator module and a photodetector (PD); the modulator module is connected to the coupler and the voltage drive module, and modulates the wavelength optical signal transmitted by the coupler under the drive of the voltage drive module; the photodetector (PD) is connected to the modulator module, converts the modulated optical signal into an electrical signal, and transmits it to the signal acquisition and processor module for spectral reconstruction.

[0032] A light source is connected to the coupler to provide the input light source. A 1550nm SLED broadband light source can be used as the input light source for the coupler, or a low-cost 850nm LED light source can be used; however, this is not a limitation. The coupler connects to multiple fiber Bragg grating sensors (…). Figure 1 The fiber Bragg gratings are sequentially labeled as Fiber Bragg grating 1, Fiber Bragg grating 2, ..., Fiber Bragg grating i, ..., Fiber Bragg grating n, for a total of n, where n is a positive integer; i is the index of the fiber Bragg grating sensor (i = 1, 2, 3, ..., i, ..., n). The broadband optical signal emitted by the light source enters the fiber Bragg grating sensor through a coupler, and each fiber Bragg grating sensor sequentially reflects its respective wavelength optical signal. The coupler also connects to the on-chip Fourier spectrometer, and the wavelength light signal reflected by the fiber optic grating. The signal enters the modulator module of the on-chip Fourier spectrometer via a coupler. This on-chip Fourier spectrometer is connected to both a voltage drive module and a signal acquisition and processing module. The signal acquisition and processing module controls the voltage drive module, which is applied to the modulator module, to emit a triangular wave drive voltage for periodic scanning. Under the voltage applied by the voltage drive module, the modulator module of the on-chip Fourier spectrometer processes the wavelength light signal reflected by the fiber Bragg grating sensor. The optical signal is modulated and converted into an electrical signal by the PD after passing through the modulator module. The signal is then acquired by the signal acquisition and processing module. The acquired signal is processed by the Fourier transform algorithm to obtain the spectral signal related to the output electrical signal of the PD. This electrical signal corresponds to the wavelength optical signal entering the modulator module. Based on this, the spectrum of the fiber Bragg grating sensor can be reconstructed. The wavelength of each fiber Bragg grating sensor is obtained by the peak finding algorithm, and finally the demodulation of the fiber Bragg grating sensor is realized.

[0033] The on-chip Fourier spectrometer receives wavelength light signals reflected from each fiber Bragg grating sensor via a coupler; these wavelength light signals then enter the modulator module. For example... Figure 2 As shown, as an optional implementation, the modulator module is an on-chip Michelson interferometer waveguide structure based on mode multiplexing.

[0034] Specifically, as an optional implementation, the modulator module includes an input waveguide, an output waveguide, a 2×2 waveguide coupler, electrodes, a first waveguide transmission arm, and a second waveguide transmission arm. The input waveguide, output waveguide, first waveguide transmission arm, and second waveguide transmission arm are respectively connected to the 2×2 waveguide coupler; the first and second waveguide transmission arms are axially symmetrical. The input waveguide is connected to the coupler, and the output waveguide is connected to the photodetector (PD). The electrodes are connected to a voltage driving module to apply a voltage V to the first and second waveguide transmission arms, thereby modulating the optical signal. Specifically, the electrodes can be respectively disposed on both sides of the first and second waveguide transmission arms (the middle region can be set as a common electrode), and the voltage V applied by the voltage driving module generates an external electric field to modulate the optical signal of the first and second waveguide transmission arms.

[0035] As an optional implementation, both the first waveguide transmission arm and the second waveguide transmission arm are asymmetric Y-waveguide structures, and each free end has reflection capability.

[0036] For example, the first waveguide transmission arm includes a first asymmetric Y-waveguide, a second asymmetric Y-waveguide, and a first waveguide ring; the first asymmetric Y-waveguide is connected to a 2×2 waveguide coupler, the first waveguide ring, and the second asymmetric Y-waveguide; the free end of the second asymmetric Y-waveguide forms a ring structure. The second waveguide transmission arm includes a third asymmetric Y-waveguide, a fourth asymmetric Y-waveguide, and a second waveguide ring; the third asymmetric Y-waveguide is connected to a 2×2 waveguide coupler, the second waveguide ring, and the fourth asymmetric Y-waveguide; the free end of the fourth asymmetric Y-waveguide forms a ring structure.

[0037] The four asymmetric Y-waveguides (first to fourth) have the same structure; therefore, their structure will be described as "asymmetric Y-waveguides." Figure 3 As shown, as an optional implementation, the asymmetric Y-waveguide includes a main waveguide, a narrow waveguide, and a wide waveguide. The narrow waveguide and the wide waveguide are respectively connected to the main waveguide, forming an asymmetric Y-shaped structure. Figure 3 , Figure 4 As shown, mode evolution is achieved between mode TE1 in the main waveguide and mode TE0 in the narrow waveguide, and between mode TE0 in the main waveguide and mode TE0 in the wide waveguide.

[0038] The wide waveguide of the first asymmetric Y-waveguide is connected to a 2×2 waveguide coupler, and the narrow waveguide is connected to the first waveguide loop. The main waveguide of the first asymmetric Y-waveguide is connected to the main waveguide of the second asymmetric Y-waveguide. The wide and narrow waveguides of the second asymmetric Y-waveguide are connected end-to-end, with the wide waveguide gradually decreasing in width to the narrow waveguide, thus connecting the wide and narrow waveguides to form a loop, as shown in the figure where the wide waveguide is connected to the narrow waveguide via a gradient waveguide. The wide waveguide of the third asymmetric Y-waveguide is connected to a 2×2 waveguide coupler, and the narrow waveguide is connected to the second waveguide loop. The main waveguide of the third asymmetric Y-waveguide is connected to the main waveguide of the fourth asymmetric Y-waveguide. The wide and narrow waveguides of the fourth asymmetric Y-waveguide are connected end-to-end, with the wide waveguide gradually decreasing in width to the narrow waveguide, thus connecting the wide and narrow waveguides to form a loop.

[0039] In addition, as a further preferred embodiment, the first waveguide ring and the second waveguide ring are both completely symmetrical structures, so as to achieve complete reflection of optical signals transmitted from the first asymmetric Y waveguide and the third asymmetric Y waveguide (narrow waveguide), respectively.

[0040] As an optional implementation method, such as Figure 2 As shown, in the first and second waveguide transmission arms of the modulator module, the first asymmetric Y-waveguide is rotationally symmetric to the second asymmetric Y-waveguide, and the third asymmetric Y-waveguide is rotationally symmetric to the fourth asymmetric Y-waveguide. Thus, the optical signal transitioning through the two main waveguides can undergo the evolution of its transmission mode in both wide and narrow waveguides during a single modulation.

[0041] In the modulator module of the above structure, the transmission modes TE0 and TE1 in the symmetrical first waveguide transmission arm and the second waveguide transmission arm are modulated twice, that is, four-fold modulation is achieved.

[0042] Wavelength light signal reflected by grating fiber optic sensor After the coupler input is fed into the on-chip Fourier spectrometer, it enters the input waveguide of the modulator module and is transmitted in transmission mode TE0. The transmitted optical signal is split into two beams at 3 dB. The two beams then enter the wide waveguides in the first asymmetric Y-waveguide of the first waveguide transmission arm and the second asymmetric Y-waveguide of the second waveguide transmission arm, respectively, for transmission. According to the mode evolution within the asymmetric Y-waveguides, the transmission mode TE0 entering the wide waveguide of the first or third asymmetric Y-waveguide will evolve into mode TE0 in the main waveguide for transmission. Figure 4 As shown.

[0043] Furthermore, after the transmission mode TE0 passes the electrodes on both arms of the modulator module, it undergoes its first modulation. The modulated transmission mode TE0 then continues to propagate into the main waveguide of the second asymmetric Y-waveguide in the first waveguide transmission arm and the fourth asymmetric Y-waveguide in the second waveguide transmission arm. Due to the optical reciprocity in the asymmetric Y-waveguide, mode TE0 in the main waveguide of either the second or fourth asymmetric Y-waveguide will evolve into mode TE0 in the wide waveguide.

[0044] like Figure 2 As shown, the width of the wide waveguide in the second and fourth asymmetric Y-waveguides gradually changes to the width of the narrow waveguide in the same waveguide, thus connecting the wide and narrow waveguides to form a ring waveguide structure. That is, the transmission mode TE0 in the wide waveguide of the second or fourth asymmetric Y-waveguide evolves into the transmission mode TE0 in the narrow waveguide and is transmitted in reverse. Similarly, according to the mode evolution of asymmetric Y-waveguides, the transmission mode TE0 in the narrow waveguide of the second or fourth asymmetric Y-waveguide evolves into mode TE1 in the main waveguide for transmission, as shown below. Figure 4 As shown.

[0045] Furthermore, the reverse transmission mode TE1 undergoes a second modulation after passing through the electrodes on both arms of the modulator module. The modulated transmission mode TE1 then continues to transmit into the main waveguide of the first asymmetric Y-waveguide in the first waveguide transmission arm and the third asymmetric Y-waveguide in the second waveguide transmission arm. Similarly, based on the optical reciprocity in the asymmetric Y-waveguide, the transmission mode TE1 in the main waveguide of the first or third asymmetric Y-waveguide will evolve into the transmission mode TE0 in the narrow waveguide. The transmission mode TE0 in the narrow waveguide of the first or third asymmetric Y-waveguide continues to transmit into the first and second waveguide rings. The first and second waveguide rings can reflect the incoming optical signal back into the narrow waveguide of the first or third asymmetric Y-waveguide, and then, through the first or third asymmetric Y-waveguide, it evolves into the transmission mode TE1 in the main waveguide of the first or third asymmetric Y-waveguide.

[0046] Furthermore, transmission mode TE1 continues forward transmission and undergoes a third modulation after passing through the electrodes on both arms of the modulator module. The modulated transmission mode TE1 continues transmission to the main waveguide in the second asymmetric Y-waveguide of the first waveguide transmission arm of the Michelson interferometer, or the fourth asymmetric Y-waveguide of the second waveguide transmission arm. It then evolves into transmission mode TE0 in the narrow waveguide of the second or fourth asymmetric Y-waveguide, and subsequently into transmission mode TE0 in the wide waveguide connected to the narrow waveguide, and then undergoes reverse transmission. Similarly, according to the mode evolution, transmission mode TE0 in the wide waveguide of the second or fourth asymmetric Y-waveguide will evolve into transmission mode TE0 in the main waveguide.

[0047] Furthermore, the transmission mode TE0 continues to transmit in reverse and undergoes a fourth modulation after passing through the electrodes on both arms of the modulator module. The modulated transmission mode TE0 is then transmitted to the main waveguide in the first asymmetric Y-waveguide of the first waveguide transmission arm or the third asymmetric Y-waveguide of the second waveguide transmission arm, and the mode evolves into the transmission mode TE0 in the wide waveguide of the first asymmetric Y-waveguide or the third asymmetric Y-waveguide. The optical signal transmitted in the wide waveguide of the first asymmetric Y-waveguide or the third asymmetric Y-waveguide continues to transmit and interferes with the 2×2 waveguide coupler in the modulator module. The interfered optical signal enters the photodetector PD through the output waveguide and is converted into an electrical signal by the photodetector PD. .

[0048] Based on the above mode multiplexing, the optical signals of the two arms of the modulator module are modulated four times. The modulated optical signals are modes TE0 and TE1, and the transmission modes TE0 and TE1 are modulated twice.

[0049] wavelength optical signal After modulation, there is a phase difference between the wavelength optical signals on the two arms. Its expression is as follows: ; In the formula, V is the applied voltage. The modulator module corresponds to the wavelength optical signal. The half-wave voltage is expressed as: ; Where L represents the length of the modulation region on a single waveguide transmission arm (such as the first waveguide transmission arm) of the modulator module, i.e., the electrode length; These represent the changes in effective refractive index for transmission modes TE0 and TE1 under the applied voltage V, respectively.

[0050] After being modulated, the wavelength optical signal is interfered with and then enters the photodetector PD through the output waveguide, where it is converted into an electrical signal. It is represented as: ; in, This indicates that the modulator module responds to wavelength optical signals. The transfer function, the electrical signal output by the photodetector PD. With the wavelength optical signal entering the modulator module There exists a correspondence (mapping relationship), therefore, the electrical signal output by the photodetector PD... After being further acquired by the signal acquisition and processing module, the wavelength optical signal entering the modulator module can be processed by the Fourier transform algorithm therein. The reconstruction, namely:

[0051] In this way, the spectral information reflected by the fiber Bragg grating sensor can be reconstructed. Furthermore, the reconstructed spectrum, through a peak-finding algorithm in the signal acquisition and processing module, allows the determination of the wavelengths of the reflected light signals from each individual fiber Bragg grating sensor. This enables the demodulation of fiber Bragg grating sensors.

[0052] The fiber Bragg grating demodulation apparatus disclosed in the above embodiments and their optional implementations is for demodulating a single-channel (n) fiber Bragg grating sensor. As another fiber Bragg grating demodulation apparatus provided in this application, it can realize multi-channel demodulation of fiber Bragg grating sensors.

[0053] Specifically, such as Figure 5 As shown, the fiber optic demodulation device includes two or more spectrometer modules, each consisting of a light source, a coupler, and an on-chip Fourier spectrometer. Figure 5 The system consists of spectrometer modules 1, 2, ..., n. Each group of spectrometer modules is responsible for connecting one (n) fiber Bragg grating sensors via its coupler. The on-chip Fourier spectrometer of each group of spectrometer modules is connected to the voltage drive module and the signal acquisition and processing module, respectively. That is, each group of spectrometer modules is driven by the voltage drive module, and the signal acquisition and processing module performs the final demodulation of the electrical signal output by the spectrometer module. The construction of a single group of spectrometer modules, voltage drive module, and signal acquisition and processing module is the same as that of the fiber Bragg grating demodulation device for a single-channel fiber Bragg grating sensor described in the previous embodiment. Therefore, the construction of the on-chip Fourier spectrometer in any group of spectrometer modules can refer to the content described in the previous embodiment, and will not be repeated here. For each group of spectrometer modules, the light source enters the corresponding fiber Bragg grating sensor through the coupler, and the wavelength light signal is reflected back by the fiber Bragg grating. The signal is modulated by an on-chip Fourier spectrometer (modulation is performed under the action of a voltage-driven module) and then converted into photoelectric signal. The signal acquisition and processing module then reconstructs the fiber Bragg grating sensor spectrum and demodulates the wavelength of the reflected light signal, thereby realizing the demodulation of the multi-channel fiber Bragg grating sensor.

[0054] The fiber Bragg grating demodulation device designed in this application utilizes a small number of miniature components to construct the fiber Bragg grating demodulation product, achieving low-cost and miniaturized design, facilitating mass production and large-scale application. Based on the demodulation of single-channel fiber Bragg grating sensors, it can be flexibly and conveniently expanded to support the demodulation of multi-channel fiber Bragg grating sensors as needed.

[0055] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A fiber Bragg grating demodulation device, characterized in that, include: At least one set of spectrometer modules; each spectrometer module includes a light source, a coupler, and an on-chip Fourier spectrometer; each set of spectrometer modules is used to connect to one fiber Bragg grating sensor; Each group of spectrometer modules is connected to a voltage drive module and a signal acquisition and processing module, respectively. Under the voltage applied by the voltage drive module, each group of spectrometer modules modulates the wavelength light signal reflected by the fiber optic grating sensor, performs photoelectric conversion on the modulated signal, and transmits the converted electrical signal to the signal acquisition and processing module for wavelength light signal reconstruction.

2. The fiber optic grating demodulation device as described in claim 1, characterized in that, The on-chip Fourier spectrometer includes a modulator module and a photodetector; the modulator module is connected to the coupler, the voltage drive module and the photodetector respectively, so as to modulate the wavelength optical signal transmitted by the coupler under the voltage applied by the voltage drive module; The photodetector is used for photoelectric conversion of the modulated signal; The photodetector is connected to the signal acquisition and processing module.

3. The fiber optic grating demodulation device as described in claim 2, characterized in that, The modulator module includes an input waveguide, an output waveguide, a 2×2 waveguide coupler, electrodes, a first waveguide transmission arm, and a second waveguide transmission arm. The input waveguide, output waveguide, first waveguide transmission arm, and second waveguide transmission arm are respectively connected to the 2×2 waveguide coupler. The first waveguide transmission arm and the second waveguide transmission arm are axially symmetrical to each other. The electrodes are connected to the voltage driving module to apply the voltage applied by the voltage driving module to the first waveguide transmission arm and the second waveguide transmission arm.

4. The fiber optic grating demodulation device as described in claim 3, characterized in that, Both the first waveguide transmission arm and the second waveguide transmission arm are asymmetric Y-waveguide structures, and each free end has reflection capability.

5. The fiber optic grating demodulation device as described in claim 4, characterized in that, The first waveguide transmission arm includes a first asymmetric Y-waveguide, a second asymmetric Y-waveguide, and a first waveguide ring; the first asymmetric Y-waveguide is connected to the 2×2 waveguide coupler, the first waveguide ring, and the second asymmetric Y-waveguide; the free end of the second asymmetric Y-waveguide forms a ring structure; the second waveguide transmission arm includes a third asymmetric Y-waveguide, a fourth asymmetric Y-waveguide, and a second waveguide ring; the third asymmetric Y-waveguide is connected to the 2×2 waveguide coupler, the second waveguide ring, and the fourth asymmetric Y-waveguide; the free end of the fourth asymmetric Y-waveguide forms a ring structure.

6. The fiber optic grating demodulation device as described in claim 5, characterized in that, Each asymmetric Y-waveguide includes a main waveguide, a narrow waveguide, and a wide waveguide; the narrow waveguide and the wide waveguide are respectively connected to the main waveguide.

7. The fiber optic grating demodulation device as described in claim 6, characterized in that, In the first waveguide transmission arm, the first asymmetric Y-waveguide and the second asymmetric Y-waveguide are rotationally symmetric; in the second waveguide transmission arm, the third asymmetric Y-waveguide and the fourth asymmetric Y-waveguide are rotationally symmetric.

8. The fiber optic grating demodulation device as described in claim 6, characterized in that, The wide waveguide of the first asymmetric Y-waveguide is connected to the 2×2 waveguide coupler, and the narrow waveguide is connected to the first waveguide loop; the main waveguide of the first asymmetric Y-waveguide is connected to the main waveguide of the second asymmetric Y-waveguide; the wide waveguide and narrow waveguide of the second asymmetric Y-waveguide are connected end-to-end; the wide waveguide of the third asymmetric Y-waveguide is connected to the 2×2 waveguide coupler, and the narrow waveguide is connected to the second waveguide loop; the main waveguide of the third asymmetric Y-waveguide is connected to the main waveguide of the fourth asymmetric Y-waveguide; the wide waveguide and narrow waveguide of the fourth asymmetric Y-waveguide are connected end-to-end.

9. The fiber optic grating demodulation device according to any one of claims 1-7, characterized in that, The signal acquisition and processing module reconstructs the electrical signal according to the following configuration: The signal acquisition and processing module uses a Fourier transform algorithm to reconstruct the wavelength optical signal from the electrical signal.

10. A modulator module for a fiber Bragg grating demodulation device, characterized in that, The modulator module includes an input waveguide, an output waveguide, a 2×2 waveguide coupler, electrodes, a first waveguide transmission arm, and a second waveguide transmission arm. The input waveguide, output waveguide, first waveguide transmission arm, and second waveguide transmission arm are respectively connected to the 2×2 waveguide coupler. The first waveguide transmission arm and the second waveguide transmission arm are axially symmetrical to each other. The electrodes are connected to the voltage driving module to apply the voltage applied by the voltage driving module to the first waveguide transmission arm and the second waveguide transmission arm.

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