基于法拉第效应的光纤磁场传感技术

Magnetic-field Sensing Technique Based on the Faraday Effect

针对亚铁磁材料阐述了基于法拉第效应测量磁场的理论基础 ,讨论了传感器的响应特性和方向性 ,并分析了传感器的频率响应和噪声特性。对于 3mm长的 YIG( Yttrium Iron Garnet)样品 ,当 B≤ 60 m T时 ,传感器的输出为线性而且没有滞后作用 ;在 80 Hz的频率点的噪声相当于 1 0 n T/Hz磁场 ,传感器的频率响应在 2 .5 MHz～ 70 0 MHz以内是基本平直的。这些指标说明基于法拉第效应的光纤磁场传感器适合脉冲磁场的测量。

Magnetic-field sensors based on the Faraday effect is demonstrated using ferromagnetic iron garnets. The sensor response and directionality are discussed, and noise equivalent field and frequency response are analyzed respectively. For B ≤60 mT, linearity and no hysteresis are exhibited. Signal-to-noise measurements at 80 Hz on small (typically 5 mm diameter×3 mm long) samples of yttrium iron garnet (YIG) yield noise equivalent magnetic fields of 10 nT/Hz. Frequency response measurements exhibit virtually flat response to approximately 700 MHz.