单模锥形光纤锥区光场及超短脉冲的传输特性

根据光波导理论,采用数值方法分析了单模锥形光纤锥区传输常数和光场分布的变化情况.采用分步傅里叶法数值求解广义的非线性薛定谔方程,对超短脉冲在锥区的传输演化进行了研究.结果表明:传输常数沿拉锥方向缓慢减小,在拉锥末端迅速减小|在拉锥初始阶段,能量主要集中在纤芯中,“转换点”之后能量在纤芯和包层中重新分布,光强在拉锥末端变强|脉宽小于80 fs的超短脉冲沿锥区传输时,沿拉锥方向,脉冲不断展宽,而当脉宽大于80 fs时,脉冲展宽不明显.

Optical Field Evolution and Transmission Characteristics of Ultra-short Pulse in the Tapered Region of a Single-mode Tapered Fiber

Propagation constant and field evolution in the tapered region are discussed using numerical method based on waveguide theory.GNSE is resolved by the split-step Fourier method to study the transmission characteristics of ultra-short pulse in the tapered region.The calculated results show that at the beginning of the tapered fiber,propagation constant decreases gradually while in the end it drops dramatically.After the “transition point”,energy redistributes in the fiber,and it becomes very large in the end.It is found that pulse width is broadened along the tapered region when the pulse width is smaller than 80fs.