Polarization-dependent Characteristics Of Magneto-optical Fiber Grating

Magneto-optic fiber Bragg grating (MFBG), a kind of intelligent waveguide structure, has many advantages such as tunable photonic band gap, low nonlinear threshold power, short magneto-optic switching time, which has comprehensive potential applications in fields of optical switching, tunable comb filtering, nonlinear pulse regeneration and fiber sensors.At the present time, MFBGs are mostly investigated theoretically. So the setup of experimental measurement platform for the MFBGs is significant to do corresponding experimental research. Based on the theory relevant to the MFBGs, three measurement schemes are analyzed and the corresponding experimental measurement systems are set up.The main contents and innovations are as follows:1. An experimental platform for MFBG measurement is set up, which can not only be used to measure polarization extinction ratio (PER), polarization dependent loss (PDL) and differential group delay (DGD) now, but also is useful for other fundamental experiments such as MFBG spectrum, magnetic-field-dependent characteristics, the coupling of several effects in the future.2. A new magnetic field measurement method based on peak value of PER is proposed by analyzing the characteristics of PER in MFBG. Both theoretical analysis and OptiSystem simulation show that, the peak value of PER is linear with the logit value of applied magnetic field when the grating coupling coefficient is much larger than the magneto-optic coupling factor, which is basically in accordance with the experimental results.3. The PDL and DGD characteristics of the MFBG along with the influence of grating parameters are numerically analyzed, which are useful for the future experimental research. The experimental result shows that the spectrum of DGD drifts to long wavelength.