title: On-chip microwave photonic beamformer circuits operating with phase modulation and direct detection.
abstract: We propose and experimentally demonstrate the working principles of two novel microwave photonic (MWP) beamformer circuits operating with phase modulation (PM) and direct detection (DD). The proposed circuits incorporate two major signal processing functionalities, namely a broadband beamforming network employing ring resonator-based delay lines and an optical sideband manipulator that renders the circuit outputs equivalent to those of intensity-modulated MWP beamformers. These functionalities allow the system to employ low-circuit-complexity modulators and detectors, which brings significant benefits on the system construction cost and operation stability. The functionalities of the proposed MWP beamformer circuits were verified in experimental demonstrations performed on two sample circuits realized in Si(3)N(4)/SiO(2) waveguide technology. The measurements exhibit a 2 × 1 beamforming effect for an instantaneous RF transmission band of 3‒7 GHz, which is, to our best knowledge, the first verification of on-chip MWP beamformer circuits operating with PM and DD.
authors.forename: Leimeng
authors.initials: L
authors.lastname: Zhuang
authors.forename: Marcel
authors.initials: M
authors.lastname: Hoekman
authors.forename: Caterina
authors.initials: C
authors.lastname: Taddei
authors.forename: Arne
authors.initials: A
authors.lastname: Leinse
authors.forename: René G
authors.initials: RG
authors.lastname: Heideman
authors.forename: Adriaan
authors.initials: A
authors.lastname: Hulzinga
authors.forename: Jaco
authors.initials: J
authors.lastname: Verpoorte
authors.forename: Ruud M
authors.initials: RM
authors.lastname: Oldenbeuving
authors.forename: Paulus W L
authors.initials: PW
authors.lastname: van Dijk
authors.forename: Klaus-J
authors.initials: KJ
authors.lastname: Boller
authors.forename: Chris G H
authors.initials: CG
authors.lastname: Roeloffzen