FIBER LASER SENSOR USING AN LONG PERIOD GRATING AS A BRAGG WAVELENGTH DEMODULATION FILTER

摘要

PURPOSE: An optical fiber laser sensor system using fiber long period grating is provided to improve system stabilization, efficiency and economicity and to freely select sensor precision and operation wavelength range by constructing the entire sensor system with an optical fiber. CONSTITUTION: An FBG(Fiber Bragg Grating) used as wavelength selection mirror and sensor head is equipped on one side of a resonator, and a mirror is equipped on the other side of the resonator. An optical fiber coupler separates optical fiber laser output signal from the resonator to two equal optical signals. A Bragg wavelength converter comprises a reference arm that generates a reference current at a reference photodetector by receiving one of the two separated optical signals, and a signal arm that generates a signal current at a signal photodetector by receiving another optical signal.