一种改善频谱性能的蚀刻衍射光栅输出结构新设计

对波分复用系统中一种重要的解复用器-衍射蚀刻光栅(EDG)的输出结构进行了研究,并提出一种新的采用渐变波导和空气槽相结合的结构设计,在保持器件原有的紧凑结构的前提下极大的提高了器件的频谱特性.该结构设计不需要额外的工艺过程,并且具有很好的工艺容差性.结构的有效性通过波束传播方法(BPM)和模式传播分析(MPA)得到了验证.在所给的数值模型中,-1 dB带宽和品质因素分别比传统设计提高了1.474和1.383倍.同时,相邻信道间的串扰降低了15 dB以上,而整个结构引入的功率损耗仅仅为0.65 dB.

A Novel Design for the Output Structure of an Etched Diffraction Grating for Improving the Spectral Performance

The output structure of an etched diffraction grating is studied. By introducing a combination of tapers and air slots into the output structure, the spectral performance of the device is greatly improved with little loss penalty, while the compactness of the device is remained. The structure requires no additional fabrication process, and has a good fabrication tolerance. The beam propagation method and the guided-mode propagation analysis are used to demonstrate the advantages of the present design. In a numerical example, the -1dB passband width and the figure of merit of a designed demultiplexer are increased by 1.474 and 1.383 times, respectively, as compared to a demultiplexer with a conventional structure. Furthermore, the crosstalk is reduced by more than 15 dB and the loss penalty is only about 0.65 dB.