All-fiber magnetic-field sensor based on a device consisting of a microfiber knot resonator and magnetic fluid is proposed for the first time in this Letter. Sensor principles and package technology are introduced in detail. Experimental results show that the resonance wavelength of the proposed sensor regularly varies with changes to the applied magnetic field. When the magnetic field is increased to 600 Oe, the wavelength shift reaches nearly 100 pm. Moreover, the sensor responding to the 50 Hz alternating magnetic field is also experimentally investigated, and a minimal detectable magnetic-field strength of 10 Oe is successfully achieved.
© 2012 Optical Society of America
Original Manuscript: September 26, 2012
Revised Manuscript: November 9, 2012
Manuscript Accepted: November 18, 2012
Published: December 12, 2012
Xianli Li and Hui Ding, "All-fiber magnetic-field sensor based on microfiber knot resonator and magnetic fluid," Opt. Lett. 37, 5187-5189 (2012)