| 摘要 |
PURPOSE:To obtain an optical fiber strand where a clad mode light is not propagated, by providing an inside coating whose transmission loss for a used wavelength is a prescribed value or larger to absorb the clad mode propagated light. CONSTITUTION:With respect to the optical fiber strand provided with a transparent inside coating layer 3 whose refractive index is higher than that of a clad 2 and a single or multilayered outside coating layer 4 whose refractive index is lower than said inside coating layer 3, the inside coating layer 3 has >=1dB/cm transmission loss for the used wavelength. Thus, the propagated light in the clad is emitted to the inside coating layer 3 and is absorbed by this layer 3 and is attenuated to a level which is not a matter practically, and the optical fiber strand where the clad mode light is not propagated is obtained even if it is used in an optical sensor, optical parts, etc., with a short length. |
