Optical fiber weak reflection grating array multilink demodulation and diagnosis system based on time division and wavelength division multiplexing

Abstract

The invention belongs to the technical field of optical fiber link management, and discloses an optical fiber weak reflection grating array multi-link demodulation and diagnosis system based on time division and wavelength division multiplexing, which comprises a light source, a modulator, an array waveguide grating, an optical fiber weak reflection grating array, an optical switch, a photoelectric detector, a data acquisition and processing device and a pulse generator. The optical fiber weak reflection grating array multi-link demodulation and diagnosis system can meet the requirements of link demodulation and diagnosis of a large-scale optical fiber weak reflection grating array network. According to the optical fiber weak reflection grating array multi-link demodulation and diagnosis system, a time division and wavelength division multiplexing fusion scheme is adopted, so that the logic relation and time sequence control of the optical fiber weak reflection grating array multi-link demodulation and diagnosis system are simpler; and the optical fiber weak reflection grating array multi-link demodulation and diagnosis system has better robustness and real-time performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical fiber link management, and relates to an optical fiber weak reflection grating array multi-link demodulation and diagnosis system based on time division and wavelength division multiplexing, which can simultaneously perform optical fiber identical weak reflection grating multi-link diagnosis and link fault location such as breakpoints. Background Art

[0002] With the development of fiber optic sensing technology, fiber optic sensing links are gradually developing towards large-scale, high-precision networking. The emergence of fiber optic weak reflection grating arrays has greatly improved the multiplexing capacity and sensing distance of fiber Bragg grating demodulation systems, and has made large-scale fiber optic sensing networks with high spatial resolution and high measurement accuracy a reality. At present, fiber optic weak reflection grating arrays have very important applications in the field of distributed fiber optic sensing, such as oil well exploration, petrochemicals, perimeter security, bridges and dams, aerospace and other fields.

[0003] The diagnosis of optical fiber links can be done with the help of optical time domain reflectometry. By analyzing the measurement curve of the optical time domain reflectometer, the uniformity, defects, breaks, joint coupling and other performances of the full optical fiber link can be understood. The optical time domain reflectometry technology uses the backscattering and Fresnel reflection principle of light to evaluate the signal attenuation in the link with the backscattered light signal generated during the propagation of light in the optical fiber. It can be used to measure optical fiber attenuation, joint loss, optical fiber fault point location and understand the loss distribution of the optical fiber link. The traditional method is mainly used for the diagnosis of a single link, while the time division multiplexing technology can be used to meet the diagnosis requirements of multiple links. However, this solution will make the system logic relationship and timing control more complicated, and will also reduce the robustness and real-time performance of the optical fiber link demodulation and diagnosis system (patent publication number: CN118659824A). According to the wavelength dependence of the optical fiber weak reflection grating array and the link demodulation and diagnosis requirements of the large-scale optical fiber weak reflection grating array network, the present invention proposes a new optical fiber weak reflection grating array link diagnosis system. Summary of the invention

[0004] The purpose of the present invention is to provide a fiber weak reflection grating array multi-link demodulation and diagnosis system based on time division and wavelength division multiplexing.

[0005] The technical solution of the present invention:

[0006] A fiber weak reflection grating array multi-link demodulation and diagnosis system based on time division and wavelength division multiplexing comprises a light source 1, a modulation device 2, an arrayed waveguide grating 3, a fiber weak reflection grating array 4, an optical switch 5, a photoelectric detector 6, a data acquisition and processing device 7 and a pulse generator 8; the light source 1, the modulation device 2, the arrayed waveguide grating 3 and the fiber weak reflection grating array 4 are connected in sequence, the optical switch 5 is arranged at the connection between the arrayed waveguide grating 3 and the fiber weak reflection grating array 4, the optical switch 5 is further connected to the photoelectric detector 6, the data acquisition and processing device 7 and the pulse generator 8 in sequence, and the pulse generator 8 is further connected to the modulation device 2.

[0007] The light source 1 is a tunable laser or a broadband light source. The broadband light emitted by the light source 1 is modulated by the modulation device 2 to become a pulse light beam with intensity modulation in the time domain.

[0008] The modulation device 2 is a device for modulating the intensity of the broadband light emitted by the light source 1 in the time domain. If the light source 1 is a tunable laser, the modulation device 2 is an electro-optic modulator; if the light source 1 is a broadband light source, the modulation device 2 is a semiconductor optical amplifier.

[0009] The arrayed waveguide grating 3 automatically distributes the pulse light beam modulated by the modulation device 2 in the frequency domain.

[0010] The fiber weak reflection grating array 4 is an identical weak reflection grating array with different central reflection wavelengths, and the central wavelengths of different weak reflection grating arrays correspond to the spectral channels of the fiber weak reflection grating array 4, thereby realizing wavelength division multiplexing of the fiber weak reflection grating array.

[0011] The optical switch 5 is used to realize the time domain multiplexing of the optical fiber weak reflection grating array 4, and utilizes the combination of time division multiplexing and wavelength division multiplexing to realize the addressing of the optical fiber weak reflection grating array. The optical signal reflected back by the optical fiber weak reflection grating array 4 is received by the photodetector 6 and processed by the data acquisition and processing 7, so as to obtain the time domain waveform of the grating reflected optical signal on a certain link in the optical fiber weak reflection grating array 4.

[0012] The pulse generator 8 is used to generate a pulse signal for driving the modulation device 2 and triggering the data acquisition and processing 7 .

[0013] Beneficial effects of the present invention: The present invention can meet the needs of link demodulation and diagnosis of large-scale fiber weak reflection grating array networks: Usually, the demodulation and diagnosis of traditional fiber weak reflection grating arrays can only be used for the demodulation and diagnosis of a single link, which limits the system capacity and also restricts the development of networked fiber optic systems; even if time division multiplexing technology is used to achieve multi-link demodulation and diagnosis, the introduction of numerous optical switches will make the logical relationship of the entire system very complicated. The present invention adopts a solution that combines time division and wavelength division multiplexing to make the logical relationship and timing control of the fiber weak reflection grating array multi-link demodulation and diagnosis system more concise, and also makes the fiber weak reflection grating array multi-link demodulation and diagnosis system have better robustness and real-time performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a multi-link demodulation and diagnosis system of fiber weak reflection grating array based on time division and wavelength division multiplexing. DETAILED DESCRIPTION

[0015] The specific implementation modes of the present invention are described in detail below in combination with the technical solutions and the accompanying drawings, but the protection scope of the present invention shall not be limited thereto.

[0016] See also Figure 1 As shown, a fiber weak reflection grating array multi-link demodulation and diagnosis system based on time division and wavelength division multiplexing includes a light source 1, a modulation device 2, an array waveguide grating 3, a fiber weak reflection grating array 4, an optical switch 5, a photodetector 6, a data acquisition and processing 7, and a pulse generator 8. The device can be used for fiber weak reflection grating array multi-link demodulation and diagnosis.

[0017] If a tunable laser is used as the light source 1, the modulation device 2 is an electro-optical modulator, and the light output by the light source 1 is intensity modulated in the time domain by the modulation device 2; if a broadband light source is used as the light source 1, the modulation device 2 is a semiconductor optical amplifier, and the light output by the light source 1 is gain modulated by the modulation device 2.

[0018] The broadband optical signal emitted by the light source 1 becomes a pulse light beam with intensity modulated in the time domain through the modulation device 2. The arrayed waveguide grating 3 automatically distributes the pulse signal modulated by the modulation device 2 in the frequency domain. Each channel of the arrayed waveguide grating 3 is respectively connected to the optical fiber weak reflection grating array corresponding to its frequency band.

[0019] The pulse light signal divided by frequency by the array waveguide grating 3 enters the corresponding fiber weak reflection grating array 4 as a sensing carrier. The light signals reflected back by the fiber weak reflection grating array 4 with different reflection wavelengths are received by the photodetector 6 at different times. The electrical signal output by the photodetector 6 reflects the distribution of the fiber grating reflected light signal in the time domain and the change in the intensity of each fiber grating reflected light signal. After being processed by the data acquisition and processing 7, the time domain waveform of the grating reflected light signal in a certain fiber weak reflection grating array 4 is obtained, thereby realizing the demodulation and diagnosis of the entire link.

[0020] The optical switch 5 can switch the optical signal to different fiber weak reflection grating arrays at different times by controlling the transmission path of the optical signal. The fiber weak reflection grating array multi-link demodulation and diagnosis system based on time division and wavelength division multiplexing can demodulate and diagnose different fiber weak reflection gratings in different time periods, thereby realizing multiplexing in the time domain. At the same time, the pulse signal used to drive the modulation device 2 and trigger the data acquisition and processing 7 is generated by the pulse generator 8.

[0021] The fiber weak reflection grating array multi-link demodulation and diagnosis system based on time division and wavelength division multiplexing described in the present invention can provide a fiber weak reflection grating array multi-link demodulation and diagnosis solution, and the system has a simpler logical framework and better real-time performance than the traditional time division multiplexing system.

Claims

1. A fiber weak reflection grating array multi-link demodulation and diagnosis system based on time division and wavelength division multiplexing, characterized in that: The optical fiber weak reflection grating array multi-link demodulation and diagnosis system comprises a light source (1), a modulation device (2), an arrayed waveguide grating (3), an optical fiber weak reflection grating array (4), an optical switch (5), a photoelectric detector (6), data acquisition and processing (7) and a pulse generator (8); the light source (1), the modulation device (2), the arrayed waveguide grating (3) and the optical fiber weak reflection grating array (4) are connected in sequence, the optical switch (5) is arranged at the connection between the arrayed waveguide grating (3) and the optical fiber weak reflection grating array (4), the optical switch (5) is further connected in sequence to the photoelectric detector (6), the data acquisition and processing (7) and the pulse generator (8), and the pulse generator (8) is further connected to the modulation device (2).

2. The fiber weak reflection grating array multi-link demodulation and diagnosis system according to claim 1, characterized in that: The light source (1) is a tunable laser or a broadband light source. The broadband light emitted by the light source (1) is converted into a pulse light beam with intensity modulation in the time domain through a modulation device (2).

3. The fiber weak reflection grating array multi-link demodulation and diagnosis system according to claim 1, characterized in that: The modulation device (2) is a device for performing intensity modulation on the wide-spectrum light emitted by the light source (1) in the time domain.

4. The fiber weak reflection grating array multi-link demodulation and diagnosis system according to claim 3, characterized in that: When the light source (1) is a tunable laser, the modulation device (2) is an electro-optic modulator; when the light source (1) is a broadband light source, the modulation device (2) is a semiconductor optical amplifier.

5. The fiber weak reflection grating array multi-link demodulation and diagnosis system according to claim 1, characterized in that: The arrayed waveguide grating (3) automatically distributes the pulse light beam modulated by the modulation device (2) in the frequency domain.

6. The fiber weak reflection grating array multi-link demodulation and diagnosis system according to claim 1, characterized in that: The optical fiber weak reflection grating array (4) is an identical weak reflection grating array with different central reflection wavelengths, and the central wavelengths of the different weak reflection grating arrays correspond to the optical fiber weak reflection grating array (4) spectral channels respectively, thereby realizing wavelength division multiplexing of the optical fiber weak reflection grating array.

7. The fiber weak reflection grating array multi-link demodulation and diagnosis system according to claim 1, characterized in that: The optical switch (5) is used to realize time domain multiplexing of the optical fiber weak reflection grating array (4), and utilizes the combination of time division multiplexing and wavelength division multiplexing to realize addressing of the optical fiber weak reflection grating array; the optical signal reflected back by the optical fiber weak reflection grating array (4) is received by the photoelectric detector (6), and is processed by the data acquisition and processing (7), so as to obtain the time domain waveform of the grating reflected optical signal on a certain link in the optical fiber weak reflection grating array (4).

8. The fiber weak reflection grating array multi-link demodulation and diagnosis system according to claim 1, characterized in that: The pulse generator (8) is used to generate a pulse signal for driving the modulation device (2) and triggering data acquisition and processing (7).

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