D-Shaped Fiber Magnetic-Field Sensor Based on Fine-Tuning Magnetic Fluid Grating Period

This paper reports a numerical investigation of magnetic-field sensing combining a D-shaped fiber and a magnetic fluid grating. In the simulation design, a magnetic fluid was used as a magnetic sensitive material because of its strong magnetic-optic effect and good refractive index controllability. When the material was inserted into a film of a certain thickness, a magnetic fluid grating was formed. This paper also reports that the magnetic fluid grating was deposited on the flat side of the D-shaped fiber. A wavelength shift of the spectrum with an increasing magnetic field was simulated. The result showed a resonance slope existed in the near infrared and middle infrared spectral regions, and that the resonance feature could be tuned owing to the changing magnetic fluid grating period, with the resonance wavelength being blue-shifted by about 950 nm when the applied magnetic field was increased from 75 to 275 Oe. Finally, the cross effectiveness between the magnetic field and temperature was analyzed numerically. Such a structure would have potential applications in magnetic-field sensors.