Unidirectional fiber optic sensor for angular acceleration measurement.

A concept of a fiber optic sensor consisting of a light source, a fiber coil, and a two-beam interferometer measuring angular acceleration is described. The principle differs essentially from common fiber optic gyroscopes (FOGs) still exploiting the Sagnac effect but sending light of the monochromatic source only unidirectionally into the fiber coil. A change in the optical path length in the fiber coil due to the Sagnac effect maintains proportionality to angular acceleration and could be detected by means of a subsequent two-beam interferometer. The sensitivity of this approach is in contrast to common FOGs determined not only by the total surface area enclosed by the fiber turns but also by the characteristics of the particular interferometer used.