High-speed FBG interrogation system insensitive to fiber link attenuation for magnetic field sensing

摘要

A high-speed FBG interrogation method for magnetic field sensing is proposed. A FBG attached to a magnetostrictive material (Terfenol-D) was used to show the output invariance when increasing the attenuation on the optical link. This was achieved by computing the ratio between the sensing and the reference signals, both generated using different DFB lasers properly tuned. The output remained invariant to attenuations up to 12 dB. Also, the system's interrogation speed was tested and compared to a commercial solution. While the commercial model was limited by its 6 kHz sampling frequency, this method provided responses up to 60 kHz.