| 摘要 |
PURPOSE:To make measuring operation practical and to measure the cutoff wavelength of an optical fiber by winding an optical fiber which is obtained by peeling its silicone layer partially and then applying the clad peripheral surface with liquid having a larger refractive index than the clad to different diameters, and measuring light loss quantities in respective winding states. CONSTITUTION:An optical fiber 4 as a sample is arranged between the light source 1 and a light quantity measuring instrument 3, and the external diameter of the intermediate part of the optical fiber 4 is made different; and this optical fiber 4 is formed in any case by peeling the silicone layer over the entire peripheral surface partially in a long-axial direction and applying silicone oil 8 to the peripheral surface of the exposed clad 7. This silicone oil has the higher refractive index than the clad. Consequently, light propagated in the clad is emitted to the external field through the silicone layer. The optical fiber 4 is installed under respective conditions, light from the light source 1 is made incident on its end surface, and the quantity of propagated light is measured by a light quantity measuring instrument 3 to measure the light loss quantity. Then, the difference between the light loss quantities of the both is calculated and wavelength characteristics of bending loss is found from the difference. |
