| 摘要 |
PURPOSE: A submersion sensor using a fiber optic coupler is provided to accurately detect the submerged position by checking the loss of optical power due to the transit of wavelength, to improve the reliability of a sensor by increasing the optical power when water invades, and to detect multiple points. CONSTITUTION: A slit(1) is formed on a rectangular parallelepiped quartz block to sustain a slight radius of curvature of an optical fiber(3). The optical fiber is fixed in the slit. After the optical fiber is completely adhered, the cladding layer of the optical fiber is polished by using polishing powder and sandpaper. The cladding layer is properly polished not to expose the core layer to the atmosphere. Glass pane is attached to the polished portion. Then, an upper planar waveguide(2) is prepared. Upon inputting a white light source to the optical fiber, the optical power of the optical fiber is transmitted to the upper waveguide. Then, the optical fiber is filtered at a specific wavelength range. The loss of optical power due to water invasion is measured by an optical time domain reflectometer. Since the optical time domain reflectometer indicates multiple positions on the optical fiber. Therefore, the submerged position is detected accurately. |
