Nemoto S, Yip G L
Appl Opt. 1977 Mar 1;16(3):705-10. doi: 10.1364/AO.16.000705.
By using wave optics method, analytical expressions are derived for the impulse response of a self-focusing optical fiber with a core whose index profile is described by the second- and the fourth-order terms of the radial distance. Two cases are considered: (1) where all the possible propagating modes are equally excited; (2) where only the modes with no azimuthal variations are equally or unequally excited. It is shown that the shape and the rms width of the impulse response depend strongly on the fourth-order coefficient of the index distribution and on the excitation conditions. Comparison is also made between the results obtained from the wave optics method and those obtained from the ray optics method, and both results are found to be identical.
通过使用波动光学方法，推导了纤芯折射率分布由径向距离的二阶和四阶项描述的自聚焦光纤脉冲响应的解析表达式。考虑了两种情况：（1）所有可能的传播模式被同等激发；（2）仅无方位角变化的模式被同等或不同等激发。结果表明，脉冲响应的形状和均方根宽度强烈依赖于折射率分布的四阶系数和激发条件。还对波动光学方法和光线光学方法得到的结果进行了比较，发现两者结果相同。
