| 摘要 |
<p>PURPOSE:To easily reduce a drift error by providing a calibration part which measures an absolute temperature distribution from the temperature of an optical fiber to be measured at part of the optical fiber to be measured and comparing the intensity ratio of the regular and an anti-Stokes' light beam at the part with that at another part. CONSTITUTION:The calibration part consists of a light source part 1, a directional coupler 2, an optical fiber 3 for calibration, and a temperature sensor 4 and a measuring instrument consists of a spectroscope 7, photoelectric converters 8 and 9, amplifiers 10 and 11, and a signal processing part 12. The optical fiber 6 to be measured is connected by a connector 5 to the fiber 3 in series. Then laser pulses from the light source part 1 are made incident on the fiber 6 by the coupler 2 and the sensor 4 measures the temperature at the same time. Back ward scattered light generated with the laser pulses enters the measuring instrument again through the coupler 2 and is separated into the regular and anti-Stokes' light beams, which are converted into electric signals. The processing part 12 calculates the regular and anti-Stokes' signal ratio after S/N ratio improvement averaging, performs temperature conver sion processing, and adjusts an entire-area offset so that the calibration part temperature becomes as high as the measured temperature of the sensor 4. Consequently, the drift error is easily reduced.</p> |
