title: Demonstration of free space coherent optical communication using integrated silicon photonic orbital angular momentum devices.
abstract: We propose and demonstrate silicon photonic integrated circuits (PICs) for free-space spatial-division-multiplexing (SDM) optical transmission with multiplexed orbital angular momentum (OAM) states over a topological charge range of -2 to +2. The silicon PIC fabricated using a CMOS-compatible process exploits tunable-phase arrayed waveguides with vertical grating couplers to achieve space division multiplexing and demultiplexing. The experimental results utilizing two silicon PICs achieve SDM mux/demux bit-error-rate performance for 1‑b/s/Hz, 10-Gb/s binary phase shifted keying (BPSK) data and 2-b/s/Hz, 20-Gb/s quadrature phase shifted keying (QPSK) data for individual and two simultaneous OAM states.
authors.affiliation: Department of Electrical and Computer Engineering, University of California, Davis, CA 95616, USA.
authors.forename: Tiehui
authors.initials: T
authors.lastname: Su
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Scott
authors.forename: Stevan S
authors.initials: SS
authors.lastname: Djordjevic
authors.forename: Nicolas K
authors.initials: NK
authors.lastname: Fontaine
authors.forename: David J
authors.initials: DJ
authors.lastname: Geisler
authors.forename: Xinran
authors.initials: X
authors.lastname: Cai
authors.forename: S J B
authors.initials: SJ
authors.lastname: Yoo
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D012666:Semiconductors; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D012825:Silicon / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D018511:Systems Integration; D013685:Telecommunications / Q000295:instrumentation*
chemical_list: D012825:Silicon