Double-digital closed-loop optical fiber magnetometer for implementing working point control and magnetic zeroing feedback

Abstract

The invention discloses an even-number closed loop optical fiber magnetometer for achieving working point control and magnetism return-to-zero, which comprises a light source drive circuit, a light path sensing unit, a photoelectric conversion unit, an A / D conversion unit, a digital signal processing unit, a D / A conversion unit and the like, wherein the light path sensing unit comprises a DFB laser, a three-port optical circulator, an integrated optical phase modulator and the like, and has simple structure; the digital signal processing unit various control time sequences, low-frequency modulation square wave and a synchronous clock of a high-frequency sine modulation signal, completes relative demodulation of low-frequency phase drift and generates compensation phase shift digital quantity, secondarily demodulates a signal subjected to relative demodulation of the low-frequency phase drift to generate the magnetic field signal feedback quantity, forms the even-number closed loop detection, achieves the stable control and magnetism return-to-zero feedback of an interferometer orthogonal working point, improves the anti-jamming capability and the stability of the system, expands the dynamic range of measuring, and improves the sensitivity for measuring the magnetism.

Description

technical field [0001] The invention relates to a magnetic field weakening measurement technology, in particular to a dual-digital closed-loop optical fiber magnetometer which realizes operating point control and magnetic return to zero feedback. Background technique [0002] With the development of science and technology and society, the application of weak magnetic measurement technology in the fields of national defense construction, national economy and biomedicine is becoming more and more extensive. [0003] In the military field, with the development of submarine noise reduction technology in various countries, traditional sonar submarine detection can no longer meet the needs of modern anti-submarine warfare, and various non-acoustic submarine detection technologies have become research hotspots in various countries. Magnetic anomaly detection is considered to be the most reliable means to classify targets and improve the resolution of submarine attacks. At present, ...

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Problems solved by technology

[0009] The introduction of the Faraday rotating mirror FRM into the optical path eliminates the phenomenon of polarization fading, but at the same time, a large reflection noise is introduced into the optical path. Two optical isolators ISO are required to be added to the input and output ends of the light wave to eliminate it. The structure is complex and the sensitivity is low; in addition, PZT is used The phase modulator and Faraday rotating mirror are not conducive to the miniaturization of the optical path structure; the traditional fiber optic magnetometer adopts an analog closed-loop detection scheme, and the system has poor anti-interference ability

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