Brillouin light time domain analysis device and method based on dual-wavelength polarization orthogonal light

Abstract

The invention relates to the field of optical fiber sensing technology, in particular to a Brillouin light time domain analysis device and a method based on dual-wavelength polarization orthogonal light. Two beams of polarization orthogonal light with different wavelengths are used as pump light, so a four-wave mixing phenomenon between the two beams of the pump light is completely restrained and the signal to noise ratio of the tail end of a sensing optical fiber can be truly increased by 3dB. In addition, according to the invention, a direct detection mode is adopted on a detection end, so compared with a Brillouin light time domain analysis device and a method in which a heterodyning detection mode is adopted, quite expensive detection devices and time-consuming demodulation processes are omitted; and development of a Brillouin light time domain analysis system towards a dynamic measuring direction is facilitated.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, in particular to a Brillouin optical time-domain analysis device and method based on dual-wavelength polarized orthogonal light. Background technique [0002] Distributed optical fiber sensing technology has been widely used for its advantages of continuous sensing of temperature, strain and other parameter changes at any point along the optical fiber, optical fiber integrating signal sensing and transmission, and convenient for long-distance sensing and large-scale networking. All aspects of the national economy and people’s daily life, including structural safety monitoring of buildings, bridges, dams, tunnels, river embankments, aircraft, ships, factory equipment, etc., leak detection in dangerous places such as oil pipelines and high-voltage lines, and border intrusion Real-time monitoring and fault point detection of communication optical cables. [0003] Brillouin optical tim...

AI Technical Summary

Problems solved by technology

However, this method has disadvantages in application, that is, there will be serious four-wave mixing phenomenon between multi-wavelength pump light, resulting in the consumption of a large amount of pump light, thereby reducing the signal-to-noise ratio

For example, if a dual-wavelength structure is used, part of the energy of the pump light is transferred to the two sidebands generated by four-wave mixing, which causes an increase in the noise optical power and a decrease in the detection optical power, so the actual signal-to-noise ratio will not According to the ideal situation, it may be increased by 3dB and may be reduced, resulting in a decrease in system performance

In the paper "Brillouindistributedfibresensingusingphasemodulatedprobe" (Brillouin distributed optical fiber sensing using phase-modulated detection light), the dual-wavelength structure and heterodyne detection are combined to realize the Brillouin optical time-domain analysis system, but the system needs to use more expensive broadband detectors , and its demodulation process is also time-consuming

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