Optical fiber vibration measurement device and method with light source frequency shift calibration auxiliary channel

Abstract

The invention provides an optical fiber vibration measurement device and method with a light source frequency shift calibration auxiliary channel. The invention relates to the field of optical fiber distributed vibration measurement. In a traditional phase-sensitive optical time domain reflection measurement device, a frequency shift calibration auxiliary channel is added as an auxiliary channel of the measurement device to completely compensate frequency drift of a light source and eliminate phase noise of a laser. In a feed-forward loop of a light source noise suppression feed-forward structure, two paths of mutually orthogonal interference light signals are obtained based on an interferometer and a 90-degree optical mixer, respectively output to a photoelectric balance detector 1 and aphotoelectric balance detector 2, and converted into two paths of interference electric signals. The influence of random change of an optical frequency initial phase on a measurement result when the optical frequency drift amount is measured based on a single signal is avoided, and the measurement precision of an external vibration signal is improved.

Description

technical field [0001] The present disclosure relates to the field of optical fiber distributed vibration measurement, in particular to an optical fiber vibration measurement device and method with an auxiliary channel for frequency shift calibration of a light source. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art. [0003] Optical time domain reflectometry technology is based on the backscattering of light and Fresnel's reverse principle, using the backscattered light waves generated when pulsed light waves propagate in optical fibers to obtain information on energy (amplitude) attenuation, which can be used to measure optical fiber attenuation , connector loss, optical fiber fault point location, and understanding the loss distribution of optical fiber along the length, etc., are indispensable technologies in optical cable construction, mainte...

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Problems solved by technology

On the one hand, it is possible to improve the frequency stability of the light wave and reduce the phase noise by improving the laser material, keeping the ambient temperature, humidity, and atmospheric pressure stable; however, based on the existing laser manufacturing process and constant temperature, humidity, and pressure processing technology, significant Progress is not a technical method that is easy to achieve in the short term; on the other hand, the adverse effects of optical wave phase noise on vibration measurement accuracy and spatial positioning can be suppressed by designing new optical path structures and data processing methods. For digital signal processing methods, For example, based on the second difference The measurement method will be restricted by the effective bit (quantization noise) of the data acquisition card, which is only a digital signal processing method and does not fundamentally reduce the phase noise of the laser, and it is difficult to further improve the measurement accuracy of the external vibration signal

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