Abstract: A counting signal processing method for a fiber optic interferometric sensor including following steps is provided. An output intensity of the fiber optical interferometric sensor is converted into an electrical signal having the form V0+V1 cos ?(t). Then, the number of times N1 that the maximum peak values are greater than a first counting level S1 and the number of times N2 that the minimum peak values are smaller than a second counting level S2 within a specific period of time TC are counted. When the value of N1, N2 or (N1+N2) is greater than a threshold counting number Cth, a detectable induced signal occurring in a sensing area is inferred. Then, whether the detectable induced signals are caused by an intruder or otherwise is judged through an alarm identification logic, and an alarm device is triggered to send out an alarm according to the result of the judgment.

Abstract: A counting signal processing method for a fiber optic interferometric sensor including following steps is provided. An output intensity of the fiber optical interferometric sensor is converted into an electrical signal having the form V0+V1 cos ?(t). Then, the number of times N1 that the maximum peak values are greater than a first counting level S1 and the number of times N2 that the minimum peak values are smaller than a second counting level S2 within a specific period of time TC are counted. When the value of N1, N2 or (N1+N2) is greater than a threshold counting number Cth, a detectable induced signal occurring in a sensing area is inferred. Then, whether the detectable induced signals are caused by an intruder or otherwise is judged through an alarm identification logic, and an alarm device is triggered to send out an alarm according to the result of the judgment.

Abstract: A fiber-optics multiplexed interferometric current sensor is provided. A broadband light source (BLS) is adapted for providing a light wave, and a depolarizer is coupled to the BLS. A depolarizer and a wave detector are respectively coupled to a first port and a third port of an optical spliter. A passive demodulating interferometric module is coupled between a second port of the optical spliter and a sensor module array. Further, the sensor module array includes an optical coupler coupled to the other port of the passive demodulating interferometric module, multiple leading fibers coupled to the other port of the optical coupler, multiple reflectors, and multiple fiber sensing heads. A port of each fiber sensing head is coupled to the other port of the corresponding leading fiber, and the other port of each fiber sensing head is coupled to a reflector. Each fiber sensing head winds on the corresponding wire.