Magnetostriction-based fiber weak magnetic field detection system

Abstract

The invention discloses a magnetostriction-based fiber weak magnetic field detection system. A laser device serves as a light source; laser outputted by the laser device passes through an isolation device and arrives at a first coupler; and then the laser is split into two beams; and one path of beam enters fibers of a sensing arm and a reference arm. The sensing arm serves as a system magnetic field sensitive part; the fiber surface of the sensing arm is coated with a magnetostrictive material; under an external magnetic field effect, the stress changing with the magnetic field is generated inside the magnetostrictive material and then is transmitted to the fiber of the sensing arm to cause a phase change of the laser transmitted in the fiber of the sensing arm, so that a phase differenceis caused between laser transmitted in the sensing arm and the reference arm; the phase difference is transmitted to a detector by a second coupler; the detector detects an intensity interferometer signal and converts an optical signal into an electric signal; the converted signal enters a signal detection circuit for signal processing; the size of an external magnetic field is demodulated by detecting the intensity interferometer signal arriving at the detector; and then an upper computer collects and outputs a measurement result.

Description

technical field [0001] The invention belongs to the technical field of optical fiber gyroscopes, and in particular relates to a magnetostrictive-based optical fiber weak magnetic field detection system. Background technique [0002] The application of magnetic field measurement technology has penetrated into various departments such as industry, agriculture, national defense, and biology, medicine, and aerospace. In industry, the magnetic detection method is used to find ore and detect underground pipelines; in national defense, magnetic mine clearance, ship degaussing, search for weapons, detection of submarines, near-explosion mines, etc. are all inseparable from magnetic field measurement technology; in medicine. Diagnose diseases by measuring the beating of the human heart and the changes in the magnetic field in the head to make a "magnetocardiogram" and "magnetoencephalogram". These all put forward new requirements for magnetic field measurement, especially for submar...

AI Technical Summary

Problems solved by technology

First of all, the sensor has high requirements on the optical fiber and light source, which need to be carefully selected and manufactured; for the interferometric optical fiber magnetic field sensor, the polarization direction of the light participating in the interference must be consistent, but the polarization state of the light when it is transmitted in an ordinary single-mode optical fiber Random variations can occur that seriously affect system visibility, so effective depolarization fading techniques must be applied to make the sensor practical

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