| 摘要 |
To detect disturbances (changes in physical configuration) in optic communication or transmission media such as fibre-optic cables 180, a source 110 provides pulsed laser light, a circulator 150 inputs the pulsed laser light into the fibre-optic cable and receives backscattered radiation from the cable 180. Detection stage 160 detects the amplitude of radiation backscattered from the cable 180 as a function of time, the backscattered radiation being caused by pulses of laser light input into the cable 180 at a first end. Successive returns may be analysed and may be correlated to indicate the existence and/or location of a disturbance.
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