| 摘要 |
A fibre optic distributed sensing system, comprising: a light source arranged in use to generate optical signals; a means for varying the optical frequency of the optical signals; an optical sensing fibre arranged in use to receive light of a frequency corresponding to that of the varied optical signals; a means for receiving light transmitted, backscattered and/or reflected from along the optical sensing fiber; and a means for processing the received light to measure properties of the received light. Preferably the light source is a laser 701. The processing means may measure relative phase, frequency and amplitude of the received light. The frequency varying means may comprise: an optical modulator 703 arranged to generate frequency sidebands; and an optical filter 708 to select one or more modulated frequency sidebands thereby varying the frequency of light input to the fibre. The modulator may be driven by a frequency of 10 to 40 GHz. The system may further comprise an interferometer to receive the light from along the fibre. |
