Sensor device is provided with optical fibers.

摘要

PURPOSE:To widen the dynamic range of measurement by using transmitted light in an optical fiber as detecting light, increasing light quantity detected per unit time and improving S/N. CONSTITUTION:A filter 2 prevents specified light wave from a light source 9 from being transmitted but transmits other light wave from a light source 1. A beam splitter 8 has wavelength selectivity that the specified light wave is made to pass and other light wave is reflected. The specified light wave is made incident from one end of the optical fiber 4 and other light wave is made incident from the other end thereof, then the change of the output intensity of other light wave from the other end is detected by a photodetector 12. Thus, the distribution of physical quantity in the longitudinal direction of the optical fiber 4 can be measured. In the optical fiber 4, the loss characteristic in other light wave whose wavelength is different from the specified light wave is changed and the optical fiber 4 has characteristic whose variation is changed with a physical action applied from other part. By using the transmitted light in the optical fiber 4 as the detecting light, the S/N is improved because the utilization factor of the light is high.