In an optical fiber Sagnac interferometer, a fiber coupler splits the light into two paths that are connected to the opposite ends of a fiber loop. Because the clockwise path and the anticlockwise path see the same environment, the interferometer is always balanced. For measuring rotation and displacement, we place a small loop of a calculated length in the fiber that causes the polarization to be different for the clockwise and anticlockwise paths, thus frustrating the interferometer and reducing the output signal by an amount dependent on the rotation of the small coil. The top of the coil is displaced sideways on rotation.

Date Published: 17 April 2008
PDF: 5 pages
Proc. SPIE 6968, Signal Processing, Sensor Fusion, and Target Recognition XVII, 69681E (17 April 2008); doi: 10.1117/12.778364

Published in SPIE Proceedings Vol. 6968:
Signal Processing, Sensor Fusion, and Target Recognition XVII
Ivan Kadar, Editor(s)