提出一种具有光束会聚功能的单层亚波长光栅结构,该结构能实现光束会聚及四路分光。利用严格耦合波分析法和波前相位控制原理设计并优化该亚波长光栅结构,并给出具体相位设计规则。基于有限元软件COMSOL对其进行仿真分析,结果表明,当波长为1550 nm 的横磁(TM)偏振光入射时,该结构可实现四路分束,每束光功率都相等且可实现光束会聚,经计算得到总体透射率为92.670%。该亚波长光栅结构有望在光通信集成以及空间光耦合等领域得到重要应用。

This paper proposes a single-layer sub-wavelength grating structure with beam convergence function and four-way beam splitting. The structure is designed and optimized using a rigorous coupled-wave analysis method and wavefront phase control principle, and the specific phase design rules are given. The simulation results of the structure using finite element software COMSOL show that the structure can realize four-way splitting under irradiation of transverse magnetic (TM) polarizes light at 1550 nm wavelength. Moreover, the optical power of each beam is equal and beam convergence is realized. The calculated total transmittance is 92.670%. Thus, the sub-wavelength grating structure can be applied in the important fields of optical communication integration and spatial optical coupling.