Surface roughness measurement with optical fibers

A method of surface roughness measurement utilizing polarization-maintaining optical fibers is presented. The method, which is based on polarization changes in light scattered from the measured rough surface, is compared with intensity-based fiber-optic surface roughness measurement and correlated with some parameters. For intensity-based measurement, a three-branch optical fiber cable is used in which two branches are coupled to two different sources. It is concluded that the uncomplicated fiber-optic method with its compact, flexible, remote-controllable setup, allows differentiation of surface roughnesses in the range of 0.5-30.0 mu m (R/sub q/) based on measurement either of intensity or of the degree of polarization of light scattered from the rough surface.