As for the situation where dual-polarizations are needed, a sandwich structure with the rectangular lattice in the center and triangular lattice in the outer space is brought forward to reducing the confinement loss and also the differential loss.

• 在单模双偏振光子晶体光纤方面,提出一种三明治结构,其中心为矩形结构,两边为三角结构,这种结构可有效降低光纤的泄漏损耗和两偏振模的损耗比。