| 摘要 |
PROBLEM TO BE SOLVED: To improve the optically coupling efficiency of an optical fiber and an optical detector without using optical components such as a lens by using a core of comparatively high refractive index and a clad of comparatively small refractive index, and providing the core with various sectional shapes in the transmitting direction of the light. SOLUTION: An optical fiber 41 of various core diameters, for example, having at least two kinds of spots of a comparatively large diameter part 41a and a comparatively small diameter part 41b, comprises a core 51 of high refractive index and a clad 52 of low refractive index. According to this structure, by cutting the optical fiber 41 on a spot of desired diameter, the relationship between a beam size of a light emitting element mounted on a fiber end or a light receiving diameter of a photoreceptor, and a core diamter of the optical fiber 41 can be properly adjusted. Whereby the light can be effectively coupled between the light emitting element and the optical fiber or between the photoreceptor and the optical fiber without using the optical components such as a lens. |
