OPTISCHER EMPFAENGER FUER GLASFASER- UEBERTRAGUNGSSYSTEME MIT VIELEN TEILNEHMERSTATIONEN

摘要

Tapping points are provided at intervals on a continuous transmission fibre (21) of an optical transmission system. Relatively short regions of the transmission fibre core (22) are exposed at these points by removing the optical cladding (23). The exposed core region is provided with a transparent, conductive layer (24). A transparent sleeve (25) is drawn over the whole, and a conductive layer (24) is likewise provided on the internal surface of said sleeve. The cavity (26) produced is filled with liquid-crystal material. An electric field is now applied to this material and influences the refractive index of the liquid crystal. The transmission fibre is "tapped". The quantity of light energy escaping from the fibre core (in accordance with the amplitude of the field applied to the liquid crystal) is detected by a photodetector mounted in the vicinity of the cavity.