Coal mine fiber optic current sensor and control method for eliminating light source power fluctuation online

Abstract

The invention discloses a coal mine fiber current sensor for on-line elimination of power fluctuation of a light source and a control method of the coal mine fiber current sensor, and belongs to the technical field of fiber sensing. The coal mine fiber current sensor comprises the light source, a fiber circulator, a fiber polarizer, a first collimating lens, a magnetic-optical crystal, a second collimating lens, a rectangular magnetic core, a solenoid, a sensing fiber ring, a reflection membrane, a carrier conductor and a photoelectric detector. The solenoid, a rectangular iron core and the magnetic-optical crystal are introduced to an optical path of the sensor, a magnetic field excited by a driving current in the solenoid acts on the magnetic-optical crystal under a guidance effect of the rectangular iron core, the size and the polarity of a rotation angle in the magnetic-optical crystal are respectively changed by changing the size and the circulation direction of the driving current, thus, a periodic changing rule of the rotation angle in the magnetic-optical crystal is built, the rotation angles in the magnetic-optical crystal in adjacent periods are equal in size and oppositein polarity, and the influence of the power fluctuation of the light source is eliminated by differential operation on detection light intensity of the photoelectric detector in the adjacent periods.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a coal mine optical fiber current sensor and a control method for eliminating light source power fluctuations online. Background technique [0002] Optical fiber current sensors have the advantages of small size and light weight, intrinsic insulation, corrosion resistance and anti-electromagnetic interference, etc., and are especially suitable for promotion and use in coal mines. At present, optical fiber current sensors are mainly designed according to the Faraday rotation optical effect, and two main types of current sensors are derived from this. Sensing scheme, one scheme is to input a beam of linearly polarized light into the sensing fiber, the magnetic field excited by the current to be measured induces the linearly polarized light to rotate in equal proportions, and the current to be measured is obtained by detecting the rotation angle; the other s...

AI Technical Summary

Problems solved by technology

The accuracy of the first sensing scheme depends on the difference between the two orthogonal optical paths of the polarization beam splitter. Only when the two orthogonal optical paths of the polarization beam splitter are completely consistent can the influence of light source power fluctuations be eliminated. The phase modulator used in this sensing scheme is expensive, which is one of the main factors for the high manufacturing cost of fiber optic current sensors.

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