title: Pulse advancement and delay in an integrated-optical two-port ring-resonator circuit: direct experimental observations.
abstract: We report experimental observations of the negative-group-velocity (v(g)) phenomenon in an integrated-optical two-port ring-resonator circuit. We demonstrate that when the v(g) is negative, the (main) peak of output pulse appears earlier than the peak of a reference pulse, while for a positive v(g), the situation is the other way around. We observed that a pulse splitting phenomenon occurs in the neighborhood of the critical-coupling point. This pulse splitting limits the maximum achievable delay and advancement of a single device as well as facilitating a smooth transition from highly advanced to highly delayed pulse, and vice versa, across the critical-coupling point.
authors.affiliation: Department of Electrical Engineering, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
authors.forename: H P
authors.initials: HP
authors.lastname: Uranus
authors.forename: L
authors.initials: L
authors.lastname: Zhuang
authors.forename: C G H
authors.initials: CG
authors.lastname: Roeloffzen
authors.forename: H J W M
authors.initials: HJ
authors.lastname: Hoekstra