Magnetic induction intensity sensing head and magnetic induction intensity measurement method and device thereof

Abstract

The invention relates to a magnetic induction intensity sensing head and a magnetic induction intensity measurement method and a device thereof; and the invention is characterized in that a magnetic field sensing head is placed in a magnetic field to be measured, and a fiber bragg grating FPI adhered on magnetostrictive materials senses ambient temperature, offset magnetic field, modulated magnetic field and the magnetic field to be measured. A light signal emitted by a monochromatic light source enters fiber bragg grating F-P cavity and forms a similar two beam interference signal after interference to be output. Cavity length variation amount of the fiber bragg grating F-P cavity is obtained according to the two beam interference signal, and measurement value is obtained according to linear relation of the cavity length variation amount and magnetic field intensity. And finally, compensation relation between the magnetic field intensity measurement value and actual value to be measured on temperature and relation of the magnetic filed intensity and the magnetic induction intensity are utilized to obtain actual value of the magnetic induction intensity. The invention can measure both direct current magnetic field and alternate current magnetic field and has higher sensibility of measurement towards a weaker magnetic field.

Description

technical field [0001] The invention relates to a magnetic induction intensity sensor head, a magnetic induction intensity measurement method and a device thereof, and belongs to the field of optical fiber sensing and optical measurement. Background technique [0002] Magnetic field measurement is of great significance in the fields of national defense, industry and medicine. The main applications are magnetic mine clearance, weapon search, magnetic navigation, submarine detection, current measurement, mineral detection and medical instruments. For weak magnetic fields (<10 -8 There are many kinds of sensors for T), such as: fluxgate magnetometer, optical pump magnetometer and superconducting quantum interference device. Among them, the superconducting quantum interference device is the most sensitive magnetic field sensor known, with a resolution of up to 10 -14 T above, but because the system needs to work at the temperature of liquid nitrogen, the structure is compl...

AI Technical Summary

Problems solved by technology

Since the light propagates in the fiber, the loss is very small, and it is easy to be an all-fiber structure, but the temperature sensitivity of the fiber itself restricts its development.

Fiber Bragg Grating FPI is composed of two identical Fiber Bragg Gratings (hereinafter abbreviated as FBG) written in the same optical fiber. It is easy to make, but the influence of temperature is always the biggest problem that plagues Fiber Bragg Grating FPI sensors.

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