| 摘要 |
The invention relates to a measuring standard for optical attenuation measurements, consisting of an optical cable (2) having at least one artificially aged optical fibre (4) of known attenuation and known length in a cable sheath (6) which is filled with a viscous medium. The cable sheath (6) consists of a material which protects the optical fibre (4) in the long term against external influences, preferably made of stainless steel. A measuring standard is produced with which the long-term constancy of the attenuation coefficient within close tolerances is ensured for each partial section of the fibre. The measuring standard can consist of a plurality of partial fibre strands (8) of different lengths. Various partial measuring standards can thus be realised. For example, two of six partial fibre strands (8) can be connected by means of a permanent splice (10). The other fibre ends (9) end in each case in a connector socket (14). The connectors (14) can alternatively be brought into contact with each other or with the measuring device. Or, a measuring standard of maximum length can be produced from six partial strands (8). In this case, all the partial fibre strands (8) are connected in series with permanent splices (10). <IMAGE> |
