Magnetic field sensors based on D-shaped long period fiber gratings

摘要

We present a new magnetic field sensor based on D-shaped long-period fiber grating (D-LPFG). Iron thin-film wascoated on the polished surface of an LPFG to function as a sensing head. Different levels of magnetic field caused a shiftin the grating loss-dip wavelength shift. The sensing section of a D-LPFG causes a change in the effective refractiveindex both of the core mode and co-propagation cladding modes in response to the different levels of the appliedmagnetic field. The maximum shift in wavelength of 36 nm was obtained in the case of a magnetic field of 153 kA/m.