OPTICAL FIBER SYSTEM DISTRIBUTION TYPE TEMPERATURE SENSOR

摘要

PURPOSE:To obtain the temperature of a sensor with high accuracy by obtaining true Raman scattered light component obtained by subtracting conversion intensity in the object wavelength area of separated Rayleigh scattered light from the light intensity of separated stokes light, etc., and obtaining the temperature of an optical fiber for a sensor from the above-mentioned component. CONSTITUTION:Light emitted from a pulse light source 2 in a measuring device 10 is conducted to the optical fiber 20 for the sensor and excites backscattered light. A part of the backscattered light returns to the device 10 and conducted to OTDR measurement circuits 30a and 30r. In the circuits 30a and 30r, the backscattered light is converted into the light in the wavelength area where the respective central wavelengths are lambdaa and lambdar by filters 4a and 4r and enters photodetectors 5a and 5b. The signals are inputted in averaging processing circuits 6a and 6r and SN ratio is enhanced. The information is inputted in a temperature distribution arithmetic circuit 7 to obtain the temperature distribution of the optical fiber 20 for the sensor. Then, the time function of the light intensity corresponding to the light intensity of antistokes light and the Rayleigh light is inputted in the arithmetic circuit 7 so as to obtain the temperature of the optical fiber for the sensor from the true Raman scattered light component.