BOTDA distributed vibration sensing system based on dynamic phase demodulating

Abstract

The invention discloses a BOTDA distributed vibration sensing system based on dynamic phase demodulating, and belongs to the technical field of optical fiber sensors. The problem that the optical fiber distributed dynamic strain, the stress and the pressure size cannot be demodulated and calculated easily is solved. The BOTDA distributed vibration sensing system based on dynamic phase demodulating comprises a Brillouin signal output device, a fourth isolator, a narrow-band optical fiber, a phase demodulating detection device and a data collecting and signal processing system. A signal of the Brillouin signal output device is connected into the narrow-band optical fiber through the fourth isolator so that stray light can be filtered out, a light intensity signal detected and output by the phase demodulating detection device is injected, and then the data collecting and signal processing system is connected for signal demodulating. According to the BOTDA distributed vibration sensing system based on dynamic phase demodulating, the optical fiber distributed dynamic strain, the stress and the pressure size can be demodulated and calculated rapidly through a phase demodulating system, so that distributed vibration sensing is achieved, the signal detection dynamic property of the BOTDA system is improved, and the purposes of being rapid in oscillating point positioning, large in dynamic measuring range and long in measuring distance can be achieved.

Description

technical field [0001] A BOTDA distributed vibration sensing system based on dynamic phase demodulation, which calculates the wavelength drift of the BOTDA system due to dynamic strain, and calculates the magnitude of strain, stress or pressure accordingly, so as to realize distributed vibration measurement, which belongs to optical fiber The field of sensor technology. Background technique [0002] With the development of optical fiber technology, research on distributed optical fiber sensing has become one of the most representative emerging technologies. Its most notable advantage is that it can accurately measure information such as stress, temperature, vibration and damage at any point along the optical fiber. There is no need to form a circuit. According to the relationship between the spectrum and power characteristics of the backscattered light generated when the light wave propagates in the optical fiber and the external environment, it detects the distribution of...

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Problems solved by technology

[0007] However, the BOTDA system is more complicated, and there are still many shortcomings in the application:

[0008] 1. Due to the complexity of the BOTDA system, it is impossible to measure breakpoints (that is, distributed points), and the application conditions are limited;

[0009] 2. In the actual engineering application of the current Brillouin scattering signal demodulator, the system frequency scanning is difficult to maintain linearity, which limits the spatial resolution and measurement sensitivity;

[0010] 3. The measurement accuracy and spatial resolution are mutually restricted, the detection signal is generally weak, and a large number of signals need to be cumbersomely processed, etc., which restrict the application of Brillouin sensing technology in actual engineering

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