title: Silicon photonic grating-assisted, contra-directional couplers.
abstract: We demonstrate, in both theory and experiment, 4-port, electrically tunable photonic filters using silicon contra-directional couplers (contra-DCs) with uniform and phase-shifted waveguide Bragg gratings. Numerical analysis, including both intra- and inter-waveguide couplings, is performed using coupled-mode theory and the transfer-matrix method. The contra-DC devices were fabricated by a CMOS-photonics manufacturing foundry and are electrically tunable using free-carrier injection. A 4-port, grating-based photonic resonator has been obtained using the phase-shifted contra-DC, showing a resonant peak with a 3-dB bandwidth of 0.2 nm and an extinction ratio of 24 dB. These contra-DC devices enable on-chip integration of Bragg-grating-defined functions without using circulators and have great potential for applications such as wavelength-division multiplexing networks and optical signal processing.
authors.affiliation: Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC, Canada. weis@ece.ubc.ca
authors.forename: Wei
authors.initials: W
authors.lastname: Shi
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.forename: Charlie
authors.initials: C
authors.lastname: Lin
authors.forename: Han
authors.initials: H
authors.lastname: Yun
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Tom
authors.initials: T
authors.lastname: Baehr-Jones
authors.forename: Michael
authors.initials: M
authors.lastname: Hochberg
authors.forename: Nicolas A F
authors.initials: NA
authors.lastname: Jaeger
authors.forename: Lukas
authors.initials: L
authors.lastname: Chrostowski
mesh_terms: D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005374:Filtration / Q000295:instrumentation*; D008027:Light; D008962:Models, Theoretical; D017785:Photons; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation; D012825:Silicon / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D012825:Silicon