| 摘要 |
PURPOSE:To obtain an extremely wide transmission band by setting a refractive index distribution within a specific range and so selecting standardization frequency that the group delay times of the lowest order mode and the 2nd high order mode groups are made roughly equal with respect to the used wavelength. CONSTITUTION:When the radius of a core is defined as (a), the refractive index of the core center as n1, the refractive index of clad as n2, the specific refractive index difference between the core and clad as DELTA, the distance in a radial direction from the core center as (r), the refractive index distribution in the core as n(r)= n1[1-2DELTA(r/2)alpha]1/2, the wavelength used as lambda, and standardization frequency as v=2pi/lambda.n12(2DELTA)1/2, the alpha is set at 2.3-3.1 and the (v) value is so selected that the group delay times of the lowest order mode and 2nd high order mode groups are made roughly equal with respect to the used wavelength lambda. Therefore, an extremely wide transmission band is obtained, the core diameter is enlarged to more than twice as compared to conventional single mode optical fibers, and the joining with a light source is made easy. |
