High sensitivity and high precision optical fiber shape sensing measuring method and system

Abstract

The invention provides a high sensitivity and high precision optical fiber shape sensing measurement method and system. In the method, a shape sensor is divided into several sections, the change of the Brillouin frequency shift of each section is subjected to average operation to find the corresponding curvature as the bending curvature of the section, so that the curvature of each section can be solved, and thus arcs of equal length in sections are obtained; before the arcs are spliced, the coordinates and the tangent direction of the endpoint of the starting section are first selected, then the bending direction of the arcs needs to be determined, further the tail end of the arc of a previous section is connected with the head end of the arc of a next section in the series, the tangent directions are the same at the connection points, and the restoration of the overall shape is completed. The system comprises a laser, a 50:50 coupler, a first polarization controller, an arbitrary function generator, a first electro-optic modulator, an erbium-doped fiber amplifier, a circulator, a filter, a sensor, a photodetector, a data acquisition card, an isolator, a second electro-optic modulator, a microwave source and a second polarization controller.

Description

technical field [0001] The invention relates to a high-sensitivity and high-precision optical fiber shape sensing measurement method and system, and belongs to the technical field of optical fiber shape sensing measurement methods and systems. Background technique [0002] With the great breakthrough in optical fiber loss in the 1960s, optical fiber has been widely used in the fields of communication and sensing as an effective and reliable optical transmission medium. The main component of ordinary optical fiber is SiO 2 , its raw materials are abundant, and its manufacturing cost is low; because of its low density compared with commonly used metal sensors and cables, it has a smaller volume and lighter weight at the same distance, which is conducive to laying and integration. Moreover, optical fiber also has many advantages such as anti-electromagnetic interference, good electrical insulation, and good stability. It has incomparable advantages in the field of sensing with...

AI Technical Summary

Problems solved by technology

[0005] For the existing optical fiber shape sensors, most of them are based on interferometric type (fiber grating, Mach-Zehnder interferometer, etc.) and cannot perform fully distributed monitoring. The loss of the sensor increases sharply, and the sensing distance is greatly limited

The technical spatial resolution (≥20cm) proposed in long-distance sensing is not enough to deal with some scenes with small bending radii, and there are shortcomings

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