Q-Point Stabilization of Optical Fabry-Perot Interferometric Sensor

Strain/vibration detection developed by optical Fabry-Perot sensor is applied in several situations involving building health monitoring, displacement detection, underwater hydrophone and acoustic wave detection. The fiber Fabry-Perot interferometer(FFPI) serves as an excellent tool for detecting acoustic waves because its high sensitivity and high frequency response, showing advantages of being simple and compact in size, insensitive to environmental fluctuations, and suitable for point measurements with minimal cross talks.. However, poor control of the operation point has been a major factor that limits the practical application of FFPI sensors in the sensor industry. An active feedback control configuration has been proposed that uses a light source wavelength adjusting by heat-sink temperature and a feedback control circuit. This demodulation method has a simply configuration, high tuning speed, and no tuning range limit. An active feedback control system is designed and demonstrated, indicating the method is simple and easy operating. Measurements show that good tracing of Q-point was effectively realized.