title: Wide bandwidth and high coupling efficiency Si3N4-on-SOI dual-level grating coupler.
abstract: We propose and experimentally demonstrate fiber-to-chip grating couplers with aligned silicon nitride (Si(3)N(4)) and silicon (Si) grating teeth for wide bandwidths and high coupling efficiencies without the use of bottom reflectors. The measured 1-dB bandwidth is a record 80 nm, and the measured peak coupling efficiency is -1.3 dB, which is competitive with the best Si-only grating couplers. The grating couplers are integrated in a Si(3)N(4) on silicon-on-insulator (SOI) integrated optics platform with aligned waveguides in both the Si(3)N(4) and Si, and we demonstrate a 1 × 4 tunable multiplexer/demultiplexer using the Si(3)N(4)-on-SOI dual-level grating couplers and thermally-tuned Si microring resonators.
authors.forename: Wesley D
authors.initials: WD
authors.lastname: Sacher
authors.forename: Ying
authors.initials: Y
authors.lastname: Huang
authors.forename: Liang
authors.initials: L
authors.lastname: Ding
authors.forename: Benjamin J F
authors.initials: BJ
authors.lastname: Taylor
authors.forename: Hasitha
authors.initials: H
authors.lastname: Jayatilleka
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Lo
authors.forename: Joyce K S
authors.initials: JK
authors.lastname: Poon