Gambling等提出通过测量单模光纤远场辐射图,可以确定单模光纤的归一化频率V,纤芯直径2a,相对折射率差 △三个主要参数.远场法是通过一个实验能同时解决三个参数测量的好方法.本文是在Gambling等工作的基础上,在实验途径方面做了某些修改,作为远场法实验的补充.大家知道,把Snyder导出的弱导光纤HE_(11)模的近似场方程代入Fraunhofer衍射 Gambling and other proposed by measuring single-mode fiber far-field radiation patterns, you can determine the single-mode fiber normalized frequency V, core diameter 2a, the relative refractive index difference △ three main parameters. Far-field method is an experiment can be solved A good way to measure three parameters.This paper is based on Gambling and other work on the basis of some experimental ways to make some changes as far-field experiments to supplement.As we all know, the Snyder derived weak guided fiber HE_ (11) The approximate field equation of the model is put into Fraunhofer diffraction