Author(s): Zhang, Z (Zhang, Zan); Huang, BJ (Huang, Beiju); Zhang, ZY (Zhang, Zanyun); Cheng, CT (Cheng, Chuantong); Bai, B (Bai, Bing); Gao, TX (Gao, Tianxi); Xu, XB (Xu, Xiaobo); Gu, WP (Gu, Wenping); Zhang, L (Zhang, Lin); Chen, HD (Chen, Hongda)

Source: MICROMACHINES Volume: 11 Issue: 9 Article Number: 859 DOI: 10.3390/mi11090859 Published: SEP 2020

Abstract: We propose a broadband high-efficiency grating coupler for perfectly vertical fiber-to-chip coupling. The up-reflection is reduced, hence enhanced coupling efficiency is achieved with the help of a Fabry-Perot-like cavity composed of a silicon nitride reflector and the grating itself. With the theory of the Fabry-Perot cavity, the dimensional parameters of the coupler are investigated. With the optimized parameters, up-reflection in the C-band is reduced from 10.6% to 5%, resulting in an enhanced coupling efficiency of 80.3%, with a 1-dB bandwidth of 58 nm, which covers the entire C-band. The minimum feature size of the proposed structure is over 219 nm, which makes our design easy to fabricate through 248 nm deep-UV lithography, and lowers the fabrication cost. The proposed design has potential in efficient and fabrication-tolerant interfacing applications, between off-chip light sources and integrated chips that can be mass-produced.

Accession Number: WOS:000580330100001

PubMed ID: 32957465

Author Identifiers:

Author        Web of Science ResearcherID        ORCID Number

Zhang, Zan                  0000-0001-9331-9114

Xu, Xiaobo                  0000-0002-7776-3415

eISSN: 2072-666X

Full Text: https://www.mdpi.com/2072-666X/11/9/859