The present invention pertains to an optical fiber comprising a transparent core having a maximum refractive index n1 and a radius a surrounded by a layer of transparent cladding material having a refractive index no which is less than n1- The refractive indices n1 and no, the radius a, and the refractive index profile of the core are designed such that:(a) Δτj, the difference between |d(Vb)/dV|j, the normalized delay time of the jth mode and |d(Vb)/dV|0, the normalized delay time of the fundamental mode, is less than about 5 x 10-2 over a wide range of V-values where j is equal to 1 or 2 and represents the highest order mode that propagates with a low loss, 0 represents the fundamental mode, b is the propagation constant and V is the normalized frequency, and(b) the normalized waveguide dispersion Vd2(Vb)/dV2 is about equal to or less than 0.2 at V-values near Vl, the normalized cutoff frequency of the first higher order mode. A fiber exhibiting characteristics (a) and (b) is capable of providing mode equalized two-mode or three-mode and low dispersion single-mode operation.
展开▼
机译:本发明涉及一种光纤,其包括具有最大折射率n1和半径a的透明芯,该透明芯被折射率n小于n1-的透明包层材料层包围。折射率n1和no的半径为a和纤芯的折射率分布设计为:(a)Δτj,| d(Vb)/ dV | j,第j个模式的归一化延迟时间与| d(Vb)/ dV | 0,基本模式的归一化延迟时间之间的差小于在广泛的V值范围内为5 x 10-2,其中j等于1或2并表示以低损耗传播的最高阶模,0表示基本模,b为传播常数,V为归一化(b)归一化的波导色散Vd2(Vb)/ dV2在接近于V1的V值(第一高阶模的归一化截止频率)处大约等于或小于0.2。表现出特性(a)和(b)的光纤能够提供模式均衡的两模或三模和低色散单模操作。
展开▼