2×2熔锥型单模光纤耦合器的模型

选择适当的连续函数描述了熔锥型耦合器熔锥形状的渐变特性及其相互位置关系,然后分别应用局部模式理论和变分法分析了横截面沿纵向变化的锥形区域和横截面近似不变的耦合区域内的耦合行为,得出了耦合器中任一横截面处的耦合系数和耦合功率表达式计算表明,熔锥型耦合器的总功率耦合主要发生在耦合区域,在两锥形区域,对于纤芯归一化频率小于1.08的部分,也发生了相当程度的耦合为了使耦合器的理论模型更接近于实际物理情况,锥形区域的耦合作用也是不容忽略的,从而得到了一个更精细的熔锥型光纤耦合器的模型.

Model of 2×2 Fused Single-mode-fiber Couplers

The appropriate continuous functions are chosen to describe fused tapers and their ubiety in fused single-mode-fiber couplers. The local mode theory and variational technique are used to analyse the taper region with gradually changing cross section and the uniform coupling region. The expressions of coupling coefficient and coupling power at any cross section in the coupler are obtained. Numerical simulation indicates that power coupling mostly takes place over coupling region. In the two taper region, only when V-value for the core cladding guide is less than 1.08, there is effective power transfer between the two fiber. In order to make mode of fused couplers be more similar practical physical essence, power coupling in the taper region must be taken into account. A more accurate model of 2?2 fused single mode fiber couplers is obtained.