Research On Distributed Fiber Optic Vibration Sensor

Distributed fiber optic vibration sensor is a new type of sensor which is the research hotspot of sensor field at present. It is based on the vibration on the role of the optical fiber to change the characteristic parameters of the optical fiber. By detection of these characteristic parameters change to indirect restore the vibration signal. It possesses high sensitivity, big range monitoring, relatively simple system, strong anti-electromagnetic interference, and other advantages, which has replaced the traditional vibration sensor to be applied in the field of a number of occasions.In this paper we divide into defense area type interferometer sensor and location type interferometer sensor two aspects to study distributed fiber optic vibration sensor. Wherein, the defense area type interferometer sensor is the concentration of this article. First, construct a multiple defense areas type interferometer sensor system which is based on passive homodyne demodulation method. For this system design a photoelectric detector group prototype to realize 8 defense areas 24 photoelectric conversion function, meanwhile, implement passive homodyne demodulation method algorithm based on the Labview development platform, design hardware demodulation circuit, divide into buried defense area type test and fence defense area type test two aspects to obtain experimental results, analyze and compare two aspects results to verify the defense areas type interferometer sensor system functions. Second, propose a novel scheme for improving the sensitivity of Mach-Zehnder interferometer sensor using a single side band (SSB) modulation technique, which is based on the microwave photonics principle to modulate the microwave signal on the optical carrier. Since the frequency of microwave signal can be dynamically tuned, the sensitivity of sensor can be actively and tunably improved. Illustrate the applied signification of this novel scheme by comparing with the currently used tradition high sensitivity demodulation scheme.Location type interferometer sensor is one of the research hotspot of sensor field, there are various structures can be achieved location function. In this paper we construct a location type interferometer sensor system which is based on dual Mach-Zehnder structure, respectively describe the key technology of this system and signal processing algorithm, divide into four cases by changing the two parameters of the vibration location and the sampling rate to obtain the experimental results, it shows that the location accuracy is controlled within the range of±300 meters which has verified the location type interferometer sensor system functions.