title: Embedded coupled microrings with high-finesse and close-spaced resonances for optical signal processing.
abstract: Single microring resonators have been used in applications such as wavelength multicasting and microwave photonics, but the dependence of the free spectral range with ring radius imposes a trade-off between the required GHz optical channel spacing, footprint and power consumption. We demonstrate four-channel all-optical wavelength multicasting using only 1 mW of control power, with converted channel spacing of 40-60 GHz. Our device is based on a compact embedded microring design fabricated on a scalable SOI platform. The coexistence of close resonance spacing and high finesse (205) in a compact footprint is possible due to enhanced quality factors (30,000) resulting from the embedded configuration and the coupling-strength dependence of resonance spacing, instead of ring size. In addition, we discuss the possibility of achieving continuously mode splitting from a single-notch resonance up to 40 GHz.
authors.forename: Mario C M M
authors.initials: MC
authors.lastname: Souza
authors.forename: Luis A M
authors.initials: LA
authors.lastname: Barea
authors.forename: Felipe
authors.initials: F
authors.lastname: Vallini
authors.forename: Guilherme F M
authors.initials: GF
authors.lastname: Rezende
authors.forename: Gustavo S
authors.initials: GS
authors.lastname: Wiederhecker
authors.forename: Newton C
authors.initials: NC
authors.lastname: Frateschi