title: Highly efficient and perfectly vertical chip-to-fiber dual-layer grating coupler.
abstract: A novel high-efficiency silicon-chip-to-fiber grating coupler is investigated here. By introducing a dual layer grating structure with an inter-layer lateral shift to mimic 45° tilted mirror behavior, perfectly vertical coupling is successfully demonstrated. Our numerical results show that a peak silicon-chip-to-fiber coupling efficiency about 70% is possible near 1550 nm. Meanwhile, for the entire telecom C-band, i.e. wavelengths from 1530 nm to 1565 nm, the coupling efficiency is > 50% and the back reflection is less than < 1%. Our proposed high-performance silicon perfectly vertical coupling structure is suitable for interfacing with multi-core fiber platform, which may play an important role in the future CMOS photonic integration technology.
authors.forename: Ming
authors.initials: M
authors.lastname: Dai
authors.forename: Leilei
authors.initials: L
authors.lastname: Ma
authors.forename: Yelong
authors.initials: Y
authors.lastname: Xu
authors.forename: Minghui
authors.initials: M
authors.lastname: Lu
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Liu
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Chen