| 摘要 |
PURPOSE: To make it possible to obtain an optical fiber capable of propagating 2 to 3 modes with low dispersion over a wide wavelength band by specifying the difference of the standardization delay times of an optical fiber and a stand ardized waveguide dispersion value. CONSTITUTION: The difference Δτj between the standarization delay time |d(Vb)/ dV|j of the j-th mode and the standarization delay time |d(Vb)/dV|o of a basic mode is set smaller than 5×10<-2> when (b) is defined as a propagation constant and V as a standarized frequency at the time of designing the optical fiber consisting of a core having a refractive index n1 and a radius (a) and a clad having a refractive index n0 smaller than n1 . The standard waveguide dispersion Vd<2> (Vb)/dV<2> is set at 0, 2 or below in the V value of a standardization cutoff frequency of the first higher mode. As a result, the optical fiber capable of propagating the 2 to 3 modes in the wide wavelength band with the low dispersion is obtd. |
