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Proceedings Paper

Research on magnetic intensity sensor using light speed modulating method in an inner interfering optical fiber
Author(s): Yanmin Li; Mengchao Li; Gang Zheng; Songlin Zhuang
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Paper Abstract

During some special processing or under the special environment, usually the magnetic intensity must be tested with full optics system. According to the light speed can be modulated in a photorefractive material in which written volume-index grating by two laser beams in opposite direction, so as to the light signal may transmit with phase modulating due to intervening of another frequency shifting laser beam. In the experiment, the inner grating would be written in an optical fiber in which the suitable little Stannum has been doped. The periodic structure in the fiber can make the light signal reflect and the value of the phase shift is corresponding to the change of the periodic structure. With the quantum theory, the energy-band structure has a zero slope at the edges of the Brillouin zone and the group velocity of the photons at the band structure of a periodic structure is zero. According to the magneto-optical effect, the measured magnetic field may make the polarization plane change. After the two laser beams come into two ends of a fiber, the magnetic field can make their polarizations direction rotate and the interfering effect should be decreased simultaneously. During the testing period, a Sn-doped fiber is exposed to a magnetic field with linear distribution. Under this environment, the more increasing of magnetic intensity, the shorter effective interference area is in the fiber. Comparing with the light delayed signal that transmits through fiber that in or not in the magnetic field, the delaying value may be corresponded to the average magnetic intensity. The output signal light could be processed by various smart way. This research work was supported by the National Natural Science Foundation of China under grant No.60472023.

Paper Details

Date Published: 1 November 2007
PDF: 6 pages
Proc. SPIE 6423, International Conference on Smart Materials and Nanotechnology in Engineering, 64234P (1 November 2007); doi: 10.1117/12.780305
Show Author Affiliations
Yanmin Li, Univ. of Shanghai for Science and Technology (China)
Mengchao Li, Univ. of Shanghai for Science and Technology (China)
Gang Zheng, Univ. of Shanghai for Science and Technology (China)
Songlin Zhuang, Univ. of Shanghai for Science and Technology (China)


Published in SPIE Proceedings Vol. 6423:
International Conference on Smart Materials and Nanotechnology in Engineering

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