| 摘要 |
PURPOSE:To allow an approaching car sensor to exhibit superior effect in the nighttime by utilizing an optical amplification clad type optical glass fiber for the approaching car sensor. CONSTITUTION:When light from the headlights of a car running in the opposite direction is sensed by a sense hole 2 with a projection door 3 in the nighttime, the light is amplified through the clad type optical glass fiber 5 which is formed in an optical fiber 1 around a glass core 4 and has a higher refractive index than the core, and the quantity of the light is measured by a photodetecting device 6. Its light energy enters the detector of the photodetecting device 6 and converted into electric energy. The distance to the car running in the opposite direction is measured from the electric energy. Thus, the optical amplifying cald type optical glass fiber 5 is used to obtain the nighttime sensor for cars running in the opposite direction. |
