| 摘要 |
PURPOSE:To simplify the operation in refractive index measurement of a waveguide by projecting light beams deflected by a deflecting means to a prism from the same position by using a concave mirror and detecting the incident angle on the prism from the detected intensity of the guided light. CONSTITUTION:The collimated beams of light emitted from a laser light source 11 are projected via the deflecting means 12 to the concave mirror 13. The curvature of the mirror 13 is so set that the beam pass always the fixed point regardless of the polarization direction. The prism 14 is installed on the waveguide 1 in this position. A means 15 for detecting the intensity of the guided light detects the intensity of the light emitted from the end of the waveguide 1 and inputs the same to a means 16 for detecting the incident angle on the prism, by which the incident angle on the prism is detected. The relation between the intensity of the guided light and the incident angle is, therefore, previously determined with respect to a waveguide having a known refractive index and the incident angle is detectable from the intensity of the unknown waveguide in accordance with such relation; furthermore, the refractive index is obtainable. The need for moving the prism and the waveguide is thereby eliminated and the operation is simplified. |
