Long-distance distributed optical fiber positioning interference structure based on wavelength division multiplexing (WDM)

Abstract

The invention provides a distributed optical fiber positioning structure and method used for long-distance monitoring and in particular relates to a distributed optical fiber positioning interference technology based on wavelength division multiplexing (WDM). The interference technology is characterized in that two rays with different wavelengths are injected into the same sensing optical fiber, are transmitted to the port of the optical fiber, are separated by a WDM device and respectively reach own reflecting terminals along own independent optical fiber paths; and two optical waves respectively form different interferences. The disturbance position information is obtained by comparing the spectrum characteristics obtained by the two interferences, of phase signals. The structure and the method have the following advantages: the structure is simple; the rear end does not have special requirements for signal processing; and by comparing the spectrum characteristics to obtain the position information, the impact of disturbing signal amplitude variation on detection is eliminated, the average position value can be obtained by utilizing a plurality of frequency points, thus obtaining high positioning precision.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a long-distance distributed optical fiber positioning interference structure. Background technique [0002] Maintaining the security of infrastructure is a basic requirement for social stability and rapid economic development. At present, my country's long-distance monitoring of infrastructure such as oil and gas pipelines, power grids, and communication networks is mainly based on some production parameters of the facilities themselves (such as sudden pressure drops, abnormal changes in the liquid level of oil tanks at intermediate stations), manual inspections, and the monitoring of passers-by. reporting, etc. These methods are low in technical content, and generally have defects such as low efficiency, poor real-time performance, long response time, and poor anti-interference ability. Often, the alarm can only be called after the monitoring facilities...

AI Technical Summary

Problems solved by technology

[0006] But in the second prior art, because of the need to use the phase generation carrier modulation technology, the demodulation of the signal becomes relatively complicated, especially the bandwidth of the interference signal caused by the disturbance It is very wide. To accurately restore the interference phase, not only the bandwidth of the bandpass filter is required to be very wide, but also the flatness and phase shift characteristics are very high, and the signal processing is more difficult and complex.

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