基于光子晶体反射镜的刻蚀衍射光栅设计与制备

刻蚀衍射光栅作为波分复用/解复用器件，有望在光通信系统中得到广泛应用。在基于顶层硅厚度为220 nm的绝缘体上硅材料上设计并制作了一种新型刻蚀衍射光栅，该刻蚀衍射光栅引入六角晶格空气孔型光子晶体作为其反射镜。模拟结果显示，相较于传统的阶梯光栅反射镜的刻蚀衍射光栅，光子晶体反射镜的刻蚀衍射光栅在理论上可有效降低器件的制作工艺难度以及插入损耗，同时可以实现器件偏振的保持。随后仅利用一步电子束光刻工艺及一步电感耦合等离子体刻蚀工艺制作了该光子晶体反射镜的刻蚀衍射光栅。测试结果表明:该光子晶体反射镜的刻蚀衍射光栅片上损耗为9.51~11.86 dB，串扰为5.87~8.72 dB，后续可通过优化工艺条件和优化输出波导布局，进一步提高器件的性能。

Design and fabrication of an etching diffraction grating based on photonic crystal reflection mirrors

As wavelength division multiplexing/de-multiplexing devices, etching diffraction gratings (EDGs) are promising to be widely used in the optical communication systems. A new kind of EDG was designed and fabricated on silicon on insulator (SOI) platform with top silicon layer of 220 nm, which applied hexagonal-lattice air-hole photonic crystals as its reflection mirrors. Simulated results show that compared with the traditional EDGs based on stepped-grating reflection mirrors, the EDG based on photonic-crystal reflection mirrors could reduce the fabrication difficulty, decrease the insertion loss and realize the polarization maintenance theoretically. Afterwards, the EDG based on photonic-crystal reflection mirrors was fabricated with one step of deep ultraviolet lithography (DUVL) and one step of inductively coupled plasma (ICP) etching. The measured results show that the insertion loss of the device is 9.51-11.86 dB, and the crosstalk of it is 5.87-8.72 dB, which can be further improved by optimizing its fabrication process and optimizing the location of the output waveguides.