However, if the beam Angle for the direct light is too wide then it will violate the limits of a full cutoff classification.
然而，如果给直接的光光线角度太宽，那么它将会违犯完整近路分类的极限。
2
The modal cutoff properties and exciting conditions of higher order resonant modes for Ge-doped photonic crystal fiber Bragg grating(PCFBG) are investigated using beam propagation method(BPM).