论文部分内容阅读
为了在保持所需宽频带特性的同时,增大光纤直径、便于连接,本文提出了一种双模光纤。它采用新的原理,即合适地选择纤芯的折射率分布,以相等的群延迟时间来传输低次双模群(LP_(01)和 LP_(11)模),本文在讲清了这种光纤的各种传输特性后,为光纤制造提供了设计资料。在幂次方折射率分布的情况下,双模群的群延迟时间差为100微微秒/公里以下时,制造偏差的允许度(由幂次方指数α=4.85±0.25,归一化频率 v=4.45±0.11的条件给出)大约是由阶跃形光纤传输双模时所能得到的允许度的5倍。另外,当折射率差△=0.3%,波长λ =1.25微米时,纤芯直径就为16.3微米,大约相当于原来的阶跃形单模光纤的2倍。这样,双模光纤就有可能既保持宽频带特性又减小连接时在技术方面存在的困难。
In order to maintain the required broadband characteristics, while increasing the diameter of the fiber, easy to connect, this paper presents a dual-mode fiber. It adopts the new principle that the refractive index distribution of the core is properly selected and the low-order bimodulus (LP_ (01) and LP_ (11) modes) is transmitted with an equal group delay. This article clarifies this After the various transmission characteristics of the optical fiber, it provides the design information for the optical fiber manufacturing. In the case of the power spectral refractive index distribution, the allowable degree of manufacturing deviation (power exponent α = 4.85 ± 0.25 and normalized frequency v = 100) when the group delay time difference of the bimodulus group is 100 picoseconds / km or less, 4.45 ± 0.11) is approximately 5 times the permissible degree that can be achieved by transmitting dual mode with step-shaped fibers. In addition, when the refractive index difference Δ = 0.3%, the wavelength λ = 1.25 μm, the core diameter is 16.3 μm, which is about twice as large as that of the conventional step-shaped single-mode optical fiber. In this way, it is possible for dual-mode fiber to maintain both the broadband characteristics and the technical difficulties associated with connecting.