| 摘要 |
PURPOSE:To enable intensity of light to be measured and adjusted with the simple constitution of providing a light attenuating filter device between the first optical fiber and a refractive index distribution lens or between a refractive index distribution lens and the second optical fiber. CONSTITUTION:A light attenuating filter 4 is provided to the ray region 3' of the exit light from an optical fiber 1 and may be changed over to various quantities of attenuation by rotating the same about a rotating axis 41. The attenuated light is received and focused in a refractive index distribution lens 5 and is again transmitted by an optical fiber 6. Since there is a gap between the optical fiber 1 and lens 5, the exit light from the optical fiber 1 does not become parallel beam and diffuses. Hence, even if the light attenuating filter 4 is installed with its normal being paralleled to the optical axis, incidence of the reflected light to the optical fiber 1 does not occur and the rotating mechanism of the light attenuating filter 4 becomes simple. |
