| 摘要 |
PCT No. PCT/GB89/01454 Sec. 371 Date Jun. 25, 1991 Sec. 102(e) Date Jun. 25, 1991 PCT Filed Dec. 5, 1989 PCT Pub. No. WO90/06498 PCT Pub. Date Jun. 14, 1990.A method is described of detecting loss in a branched optical fibre network comprising a first optical fibre (1) and a plurality of second optical fibres (3) each of which is coupled to the first optical fibre. The first optical fibre (1) constitutes a main line. The method comprises the steps of launching a pulse into the main line (1) and monitoring the main line for changes in attenuation of reflected signals returning from the reflectors (5). |
