For The Development Of Interferometric Optical Fiber Sensors In The Fields Of Oil And Gas Exploration And Security

From the 1980s,optical fiber sensors have been rapidly developed,especially the interference type optical fiber sensor.It has the advantages of high detection accuracy,easy multiplex networking and large dynamic operation range.It is widely used in oil and gas exploration,security monitoring,submarine anti-submarine warfare,seismic wave detection and other fields.In this dissertation,a prototype of an interferometric optical fiber acceleration sensor system used in the field of oil and gas exploration and an interference vibration cable system prototype used in the field of perimeter security monitoring have been developed to provide technical support for the practical application of the product.The work done in this dissertation includes the following content:In the development of interferometric fiber-optic sensors for oil and gas exploration,based on the principle of Michelson interferometer,a two-end fixed beam optical fiber acceleration sensors is researched and fabricated.The phase sensitivity of the sensor is theoretically analyzed and tested.The results show that the sensitivity of the sensor is related to the quality of the vibrator and the coil length of the optical fiber.When the coil length is about 13 meters and the mass of vibrator is about 29 grams,the sensitivity of the sensor can reach about 1698 rad/g,and the resonance frequency is about 300Hz.The field test of the sensor array,including noise test,crosstalk test,response test.The results show that the average phase noise of the sensor array is about 5×10-4rad/(?)Hz@100Hz,the average TDM crosstalk is about-76.45dB.The results prove that the designed sensor array can meet the actual application of oil and gas exploration.In the development of interference-type optical fiber sensors for security,the system is based on the principle of Michelson interferometer,adopts the structure of vibration cable.A demodulation method based on high-speed binary rectangular-pulse phase modulation is researched.The method uses the high-frequency square wave modulated by a phase modulator to generate three phase-shifted intensity signals at the output.The results show that the method can accurately estimate the vibration demodulation.Vibration cable network for a variety of responses to the test and found that the system can well identify a variety of intrusion signals.A set of alarm algorithm based on time-domain crossing statistics is researched and applied to the perimeter security system.Experiments show that the algorithm can make a accurate alarm judgment.Finally,the alarm software is designed including principle,functional point analysis and realization.After a long time testing shows that the system false alarm rate is less than 1%and without alarm failure.It proves that the system can be well applied to the perimeter security area.