title: Continuously apodized fiber-to-chip surface grating coupler with refractive index engineered subwavelength structure.
abstract: We demonstrate a fully etched, continuously apodized fiber-to-chip surface grating coupler for the first time (to our knowledge). The device is fabricated in a single-etch step and operates with TM-polarized light, achieving a coupling efficiency of 3.7 dB and a 3 dB bandwidth of 60 nm. A subwavelength microstructure is employed to generate an effective medium engineered to vary the strength of the grating and thereby maximize coupling efficiency, while mitigating backreflections at the same time. Minimum feature size is 100 nm for compatibility with deep-UV 193 nm lithography.
authors.affiliation: Departamento Ingeniería de Comunicaciones, ETSI Telecomunicación, Universidad de Málaga, 29010 Málaga, Spain. robert.halir@ic.uma.es
authors.forename: R
authors.initials: R
authors.lastname: Halir
authors.forename: P
authors.initials: P
authors.lastname: Cheben
authors.forename: J H
authors.initials: JH
authors.lastname: Schmid
authors.forename: R
authors.initials: R
authors.lastname: Ma
authors.forename: D
authors.initials: D
authors.lastname: Bedard
authors.forename: S
authors.initials: S
authors.lastname: Janz
authors.forename: D-X
authors.initials: DX
authors.lastname: Xu
authors.forename: A
authors.initials: A
authors.lastname: Densmore
authors.forename: J
authors.initials: J
authors.lastname: Lapointe
authors.forename: I
authors.initials: I
authors.lastname: Molina-Fernández