Magnetic Field Sensing vs. Fiber-Optic Interferometer

• Main Authors: Rong Yao Chen, 陳榮耀
• Other Authors: Allen Jong-Whang
• Format: Others
• Language: zh-TW
• Published: 1993
• Online Access: http://ndltd.ncl.edu.tw/handle/22260294876483590339

碩士 === 國立臺灣科技大學 === 工程技術研究所 === 81 === Research results of the effect of magnetic field on different materials have been successfully applied on various industrial applications, the magnetic field measurement has therefore been a popular research issue. In this paper, we will discuss a magnetic field sensing system based on fiber-optical interferometry. The system uses a Mach-Zehnder fiber-optical interfer- ometer and a magnetostrictive material with high magnetic permitivity-2605SC. Phase Tracking with DC(PTDC) technique is used to be invariant to phase shift effect caused by environmental interference, which phenomenon is probable for Mach-Zehnder type interferometers. Good system reliability and signal detection can be achieved by routing feed-back error voltage to phase shifter on the piezoelectric (PZT) fiber to maintain the phase of the interferometer at the quadrature point. We will study the linearity, frequency response, and the effect of DC bias to AC magnetic field measurement. When the DC bias equals 0.45 Oe, the system is capable of measuring the AC field (with frequency = 4.13KHz) down to 0.0088 Oe.