| 摘要 |
A data gathering system comprising a single optical fiber having one or more modulators formed thereon, means for launching into the fiber an interrogating light pulse which propagates in a first direction, means for generating at each modulator an optical return signal which propagates in the fiber in a second direction opposite the first direction and which has an intensity which is variable in response to variations in an external signal incident at the modulator, and means for detecting and processing each such return signal. The return signal comprises a portion of the interrogating light pulse which is coupled into the fiber in the second direction via evanescent coupling. The return signal from each modulator (or array of modulators) is identified via time division multiplexing. A signal processing means may be coupled to the fiber for generating a unique return signal from each of one or more modulator arrays, each array comprising a selected subset of the modulators. In a preferred embodiment, each modulator comprises a looped section of the fiber having a coupling region in which the distance between adjacent fiber segments is variable in response to variations in an external signal incident thereon. In another embodiment, each modulator comprises a short fiber segment positioned adjacent to the main fiber and separated therefrom by a distance variable in response to pressure changes incident on the modulator. |
