Abstract: A method is described for reducing the effect of linear birefringence in an optical fiber, in particular a circular-cored single-mode fiber. The invention may also be directed to an optical fiber having a reduced linear birefringence. A length of the optical fiber may be subdivided into a plurality of sections and a twist having a predetermined sense of rotation and a twist angle may be introduced between the sections. Fibers of this type may find applications, for example, in fiber-optic current and magnetic field sensors.

Abstract: A computer-executable method for diagnosing trouble causes in telephone cable segments when trouble data are available only for entire cables is presented. This method diagnoses problems in the components of processes when the component location of process problems is not known. It gives a statistical relationship between component attributes and process problem rates, to facilitate assessment and improvement of policies about the process. This method may be used for diagnosing systematic problems in segments of telephone cable connections of given central offices.