| 摘要 |
PURPOSE:To reduce the loss of light by eliminating unnecessary propagation modes by forcing light entering cladding to radiate out of an optical fiber by roughening the cladding which covers the external circumference of the core of the optical fiber. CONSTITUTION:An optical fiber 1 consists of a core 2 and cladding 3 covering its external circumference, and the external circumference 5 of this cladding 4 is roughened finely by being etched with a glass etching agent such as hydrogenfluoride. Consequently, light in unnecessary propagation mode which enters the cladding 3 without being reflected by the boundary surface of the core 2 and cladding 3 and increases in loss is eliminated without using a special additional device such as a dummy fiber. For the formation of the said rough surface 5, regular unevenness may be formed in addition to the method by the etching agent. |
