We expatiate the sensing characteristic of LPG and the influence of its metal over-cladding in order that we can provide theoretic support for the principle of this dynamic filter.

The main reasons why the dynamic gain equalization are applied in DWDM is analyzed. The kinds and primary characteristics of DGE at home and abroad are introduced.

To meet the improvement in overall network performance, not only dynamic gain spectrum adjustment (DGSA) function but also automatic gain clamp (AGC) function is needed.