title: Optimal design of an ultrasmall SOI-based 1 × 8 flat-top AWG by using an MMI.
abstract: Four methods based on a multimode interference (MMI) structure are optimally designed to flatten the spectral response of silicon-on-insulator- (SOI-) based arrayed-waveguide grating (AWG) applied in a demodulation integration microsystem. In the design for each method, SOI is selected as the material, the beam propagation method is used, and the performances (including the 3 dB passband width, the crosstalk, and the insertion loss) of the flat-top AWG are studied. Moreover, the output spectrum responses of AWGs with or without a flattened structure are compared. The results show that low insertion loss, crosstalk, and a flat and efficient spectral response are simultaneously achieved for each kind of structure. By comparing the four designs, the design that combines a tapered MMI with tapered input/output waveguides, which has not been previously reported, was shown to yield better results than others. The optimized design reduced crosstalk to approximately -21.9 dB and had an insertion loss of -4.36 dB and a 3 dB passband width, that is, approximately 65% of the channel spacing.
authors: School of Electronics and Information Engineering, Tianjin Polytechnic University, Xiqing District, Tianjin 300387, China. lihongqiang@tjpu.edu.cn
authors: Hongqiang
authors: H
authors: Li
authors: Yaoting
authors: Y
authors: Bai
authors: Xiaye
authors: X
authors: Dong
authors: Enbang
authors: E
authors: Li
authors: Yang
authors: Y
authors: Li
authors: Yu
authors: Y
authors: Liu
authors: Wenqian
authors: W
authors: Zhou
mesh_terms: D012825:Silicon / Q000737:chemistry*; D013057:Spectrum Analysis / Q000379:methods; D018511:Systems Integration
chemical_list: D012825:Silicon
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