| 摘要 |
<p>An ultra-low loss optical fiber is provided. The ultra-low loss optical fiber includes a core having the maximum refractive index inside an optical fiber, and placed at the central portion of the optical fiber, a trench having the minimum refractive index inside the optical fiber and encompassing the core, and a cladding encompassing the trench. The core includes a first sub-core layer having the maximum refractive index inside the optical fiber, and placed at the center of the optical fiber, a second sub-core layer having a refractive index lower than that of the first sub-core layer and encompassing the first sub-core layer, and a third sub-core layer having a refractive index lower than that of the second sub-core layer and encompassing the second sub-core layer.</p> |
