| 摘要 |
PURPOSE:To reduce the cost of a measuring instrument by receiving light from a light emitting element section connected to one terminal of an optical submarine cable laid already by a photodetection element section connected to the other terminal to supervise the said optical submarine cable in laying the optical submarine cables twice or over separately. CONSTITUTION:A light emitting diode or a laser diode 81 is connected between a watertight case 5 of a laid optical submarine cable 2 and a feeder line 21 and a prescribed DC voltage is applied via the feeder line 21 to the diode 81, which is emitted. The light is always received by the photodetection section (e.g., photodiode) 9 provided to a land station (not shown) through an optical fiber 21 and its level is supervised, then whether or not the optical submarine cable is subjected to disconnection or damage is detected easily. That is, since the light sent from one terminal of the optical submarine cable is utilized directly, range possible for supervision is extended up to nearly 55km of one relay section. |
