Abstract: A process of contactless monitoring the tension in an optical fiber and a tension meter which enables contactliess measurement of the tension in a bare and in a coated optical fiber. By measuring the retardation induced by the birefringence of an optical fiber by means of a polarized light beam incident to the fiber at an angle between about 10° and 25° to the detection optical axis, it is possible to accurately measure tensions over a wide range, i.e., from less than about 10 g to about 450 g. The method enables monitoring the tension during the ramp-up of the drawing process and is particularly advantageous for the control of the drawing tension in manufacturing of NZD, multimode or special fibers. Accurate monitoring of the tension both on a bare and on a coated fiber can also be achieved.

Abstract: A process of contactless monitoring the tension in an optical fibre and a tension meter which enables contactless measurement of the tension in a bare and in a coated optical fibre. By measuring the retardation induced by the birefringence of an optical fibre by means of a polarised light beam incident to the fibre at an angle between about 10° and 25° to the detection optical axis, it is possible to accurately measure tensions over a wide range, i.e., from less than about 10 g to about 450 g. The method enables monitoring the tension during the ramp-up of the drawing process and is particularly advantageous for the control of the drawing tension in manufacturing of NZD, multimode or special fibres. Accurate monitoring of the tension both on a bare and on a coated fibre can also be achieved.

Abstract: The granulometer uses a measuring laser beam (9) to illuminate particulate and, through the measure of the distribution of the light diffused by the examined particulate and gathered by a collecting lens (11), measures the concentration of particulate in the fluid in low concentration standards, the laser beam (9) being a converging one focused on a laser opaque shell (12) that partly covers the same lens.