| 摘要 |
PURPOSE:To measure temperatures in a high temperature range by making light with specific wavelength incident from one terminal of an optical fiber and detecting variation in the intensity of its back Rayleigh scattered light. CONSTITUTION:Light pulses of, e.g. about 0.78 and 1.3mum are made incident on the optical fiber F from laser diodes L1 and L2 through beam splitters 1, 2, 4, and 5. The back Rayleigh scattered light of about 0.78mum from the optical fiber F is extracted by a detector D1, whose output is monitored by a light pulse tester (OTDR)O1. When the optical fiber F is below about 700 deg.K, the spectral radiation brightness of about 0.78mum from the optical fiber F is zero and the intensity of the back Rayleigh scattered light from the optical fiber F is obtained at the OTDRO1. On the other hand, light of about 1.3mum in wavelength is supplied as an output from a detector D2 and this output is the sum of the intensity of the back scattered light of light pulses incident on the optical fiber F and the intensity of radiant light of about 1.3mum emitted by the optical fiber F when the temperature of a measurement part rises above about 500 deg.K. Thus, temperatures in a high temperature range are measured. |
