为了提高二次谐波产生转换效率，本文提出将一维周期光学超晶格两端贴上未被极化的厚度可以改变的非线性介质层，通过调整附加介质层的厚度来调制基频波的场，从而观察二次谐波产生转换效率的变化情况.结果表明:基频波场可以很大程度地调制二次谐波产生;随着能量的增加，二次谐波产生转换效率增加，随着能量的减小，二次谐波产生转换效率减小;当达到透射共振(透射率等于1)时，转换效率最大，此时相对于传统样品(将光学超晶格置于无限大的非线性背景中)，二次谐波产生转换效率最多可以提高到1.5倍左右；而相对于实际样品(将光学超晶格置于空气中)，二次谐波产生转换效率最多可以提高到3.3倍.因此可以得到结论：透射共振对二次谐波产生有增强的作用，可以很大程度上提高其转换效率.

In order to increase the second harmonic generation conversion efficiency, the periodic optical superlattice was sandwiched with nonpoled and nonlinear media with finite and variable width, which can bring about the significant modulation for the fundamental wave with changing the thickness of the additional media. It is found that: the conversion efficiency increases or reduces when the energy of fundamental wave increases or reduces; it can be enhanced significantly when transmission resonance (the rate of transmission obtains 1) takes place; compared with the conventional sample (the optical superlattice embedded in infinite and nonlinear media), the second harmonic generation conversion efficiency is enhanced 1.5 times at most; for the practical sample (the optical superlattice embedded in air), it can be enhanced 3.3 times at most. So the second harmonic generation conversion efficiency can be enhanced apparently by the transmission resonance.