title: Giant electro-optic effect in Ge/SiGe coupled quantum wells.
abstract: Silicon-based photonics is now considered as the photonic platform for the next generation of on-chip communications. However, the development of compact and low power consumption optical modulators is still challenging. Here we report a giant electro-optic effect in Ge/SiGe coupled quantum wells. This promising effect is based on an anomalous quantum-confined Stark effect due to the separate confinement of electrons and holes in the Ge/SiGe coupled quantum wells. This phenomenon can be exploited to strongly enhance optical modulator performance with respect to the standard approaches developed so far in silicon photonics. We have measured a refractive index variation up to 2.3 × 10(-3) under a bias voltage of 1.5 V, with an associated modulation efficiency V(π)L(π) of 0.046 V cm. This demonstration paves the way for the development of efficient and high-speed phase modulators based on the Ge/SiGe material system.
authors.affiliation: L-NESS, Dipartimento di Fisica, Politecnico di Milano, Polo di Como, Via Anzani 42, I 22100 Como, Italy.
authors.forename: Jacopo
authors.initials: J
authors.lastname: Frigerio
authors.affiliation: Institut d'Electronique Fondamentale, Univ. Paris-Sud, CNRS UMR 8622, Bât. 220, 91405 Orsay Cedex, France.
authors.forename: Vladyslav
authors.initials: V
authors.lastname: Vakarin
authors.affiliation: Institut d'Electronique Fondamentale, Univ. Paris-Sud, CNRS UMR 8622, Bât. 220, 91405 Orsay Cedex, France.
authors.forename: Papichaya
authors.initials: P
authors.lastname: Chaisakul
authors.affiliation: L-NESS, Dipartimento di Fisica, Politecnico di Milano, Polo di Como, Via Anzani 42, I 22100 Como, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Ferretto
authors.affiliation: L-NESS, Dipartimento di Fisica, Politecnico di Milano, Polo di Como, Via Anzani 42, I 22100 Como, Italy.
authors.forename: Daniel
authors.initials: D
authors.lastname: Chrastina
authors.affiliation: Institut d'Electronique Fondamentale, Univ. Paris-Sud, CNRS UMR 8622, Bât. 220, 91405 Orsay Cedex, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Le Roux
authors.affiliation: Institut d'Electronique Fondamentale, Univ. Paris-Sud, CNRS UMR 8622, Bât. 220, 91405 Orsay Cedex, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Vivien
authors.affiliation: L-NESS, Dipartimento di Fisica, Politecnico di Milano, Polo di Como, Via Anzani 42, I 22100 Como, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Isella
authors.affiliation: Institut d'Electronique Fondamentale, Univ. Paris-Sud, CNRS UMR 8622, Bât. 220, 91405 Orsay Cedex, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Marris-Morini