Magnetic field sensor based on photonic crystal fiber and optical grating and measurement method

Abstract

The invention provides a magnetic field sensor based on a photonic crystal fiber and an optical grating and a measurement method. The magnetic field sensor consists of the D-shaped photonic crystal fiber, a nanogold layer, the nano optical grating and magnetofluid film, wherein the nanogold layer is coupled to the axially extending smooth surface of the D-shaped photonic crystal fiber, the nano optical grating is inscribed on the nanogold layer, the magnetofluid film covers the nano optical grating, and the structures of the D-shaped photonic crystal fiber and the nano optical grating improvethe intensity of evanescent waves. The refractive index of a magnetofluid changes with the change of magnetic field intensity, free electrons on the surface of the nanogold layer produce absorbing peaks through resonance, their resonant wavelengths offset, magnetic field sensing measurement is achieved by observing the offset process of the resonant wavelengths, a surface plasmon resonance principle is adopted, and the problem of poor linearity of an optical fiber magnetic field sensor prepared by utilizing magnetofluid refraction index characteristics is solved only analyzing the resonance relation of the magnetofluid and the nanogold layer and the more obvious linear relation between the absorbing peaks and magnetic fields.

Description

Technical field: [0001] The invention relates to the field of optoelectronic technology, in particular to a magnetic field sensor and a measurement method based on a photonic crystal fiber and a grating. Background technique: [0002] Magnetic field, as the carrier of information, has become an important means of obtaining information in today's human society. Therefore, magnetic field sensing technology occupies an important position in information technology. The optical fiber magnetic field sensor has been widely concerned by the advantages of simple structure, anti-interference, high sensitivity and so on. In the 1990s, Russell P and others proposed photonic crystal fiber (document 1. RussellP. Photonic crystal, fibers [J]. Science, 2003, 299 (5605): 358-362.), this structure has low loss, can Controlled nonlinearity, strong birefringence, and uncut single-mode characteristics (document 2.Knight J C, Birks TA, Russell P S J, et al.Properties of photonic crystal fiber a...

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Problems solved by technology

However, most of these structures are based on optical absorption sensing methods, and the large transmission path and absorption coefficient will affect the observation of optical signals.

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