硅基片上刻蚀衍射光栅及其平坦化设计

Etching diffraction grating of silicon substrate and design of flatten

刻蚀衍射光栅(EDG)作为实现波分复用功能的关键器件,对于片上光互连的实现至关重要。为了实现1310nm波段通道间隔为20nm的硅基EDG,采用了基尔霍夫标量衍射理论仿真方法进行理论设计和仿真验证,通过在闪耀光栅反射面引入布喇格反射光栅来提高反射效率、降低器件插入损耗,并在入射波导处引入多模干涉耦合器以实现通道频谱平坦化设计。结果表明,闪耀光栅反射面的反射效率由35%提高到了85%,1d B带宽达到12nm。这对于提高系统稳定性、增大传输距离和容量、降低系统成本具有显著作用,能够满足光互连系统的实际应用需求。

Etching diffraction grating( EDG),one of the most critical components,can achieve wavelength division multiplex( WDM) function and realize on-chip optical interconnection. In order to realize 4-channel EDG with the wavelength spacing of 20 nm at 1310 nm wavelength,Kirchhoff scalar diffraction theory was used for theory design and simulation verification.To further improve the reflection efficiency and decrease the insertion loss,Bragg reflection gratings were designed to replace the normal etched facets. Multimode interference( MMI) coupler was also introduced at input waveguide for flat-top frequency response. The simulation results demonstrate the reflection efficiency of grating reflective surface is up to 85% and 1d B bandwidth is up to 12 nm. The designed EDG has a significant effect on improving system stability,increasing transmission distance and capacity, and reducing system cost. The design can meet the practical application requirements of optical interconnection system.