Brillouin optical time-domain reflectometer based on multimode optical fiber

Abstract

The invention discloses a Brillouin optical time-domain reflectometer based on a multimode optical fiber. The Brillouin optical time-domain reflectometer comprises a laser, a polarization controller, a first variable optical attenuator, an electro-optical modulator, a pulse generator, a bias controller, an optical fiber coupler, a second variable optical attenuator, a first erbium-doped optical fiber amplifier, a first isolator, a first grating filter, a third variable optical attenuator, a multimode optical fiber circulator, a second erbium-doped optical fiber amplifier, a second isolator, a second grating filter, a fourth variable optical attenuator, a scrambler, a multimode sensing optical fiber, a photoelectric detector, a band-pass filter, a data acquisition device and a data processing terminal. According to the invention, the Rayleigh scattering signal and the spontaneous Brillouin scattering signal in the optical fiber interact with each other, the influence of light source frequency drift is eliminated, the stability is good, a frequency shift reference light path is not needed, and the system structure is simplified.

Description

technical field [0001] The invention belongs to the field of distributed optical fiber sensing, in particular to a multimode optical fiber-based Brillouin optical time domain reflectometer. Background technique [0002] In industries such as electric power, petroleum, bridges, and railways, distributed optical fiber sensing technology relies on the characteristics of small size, light weight, anti-electromagnetic interference, and can be used as sensing and transmission elements at the same time, as well as distributed measurement and fault location. Capabilities have attracted extensive attention and have been successfully applied in the above fields. [0003] The distributed optical fiber sensing technology based on Brillouin scattering can be divided into Brillouin Optical Time Domain Reflectometry (BOTDR) and Brillouin Optical Time Domain Analysis (BOTDA) according to different detection signals. Different from Brillouin optical time-domain analysis for detecting stimul...

AI Technical Summary

Problems solved by technology

However, the reference light and the self-Brillouin scattered light that has undergone the sensing process will be affected by factors such as the frequency drift of the light source during the heterodyne detection process, and the corresponding frequency shift operation will also increase the complexity of the system.

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