Pulse pre-pumping single-ended vector botda dynamic strain measurement method and device

Abstract

The invention provides a pulse pre-pumping single-ended vector BOTDA dynamic strain measuring method and measuring device. Stepped pulsed light is utilized to be incident from one end of a sensing fiber, spontaneous Brillouin scattered light generated by a 0-order baseband pre-excited sound wave field of time-limited microwave modulation pre-pumping pulsed light and back Rayleigh scattered light generated by a 1-order sideband serve as probe light, and both generate an excited Brillouin scattering effect with sensing pulsed light; frequency beating of local oscillator light and the probe light carrying Brillouin scattering information is performed in a balance detector, in-phase and orthogonal components in an electrical signal which are obtained after frequency beating are utilized to obtain an excited Brillouin scattering phase shift value, and finally a corresponding dynamic strain value is demodulated according to a corresponding relation curve of phase shifts and dynamic strain which is stored in a computer. The pulse pre-pumping single-ended vector BOTDA dynamic strain measuring device is simple in structure and convenient to use, can effectively reduce a non-local effect, improves a signal to noise ratio of a system, and can realize dynamic strain measurement with wide band, high spatial resolution and measurement accuracy, and good reliability and stability.

Description

technical field

[0001] The invention relates to a method and a device for realizing vector BOTDA dynamic strain measurement of a single-end structure by using a pulse pre-pumping technology and an optical fiber Rayleigh scattering principle, and belongs to the field of measurement technology. Background technique

[0002] The distributed optical fiber sensor based on Brillouin Optical Time Domain Analysis (BOTDA) technology utilizes the Stimulated Brillouin Scattering (SBS) effect between the probe light and pump light transmitted in opposite directions. , the high-frequency pump light transfers energy to the low-frequency Stokes probe light, and the probe light is amplified by the stimulated Brillouin effect. Therefore, the received signal strength is high, the measurement accuracy is high, and the dynamic range is wide. With its comprehensive performance advantages, BOTDA technology is widely used in submarine optical cable manufacturing and construction maintenance, oil a...

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