Affiliation:
1. R-DEX System
2. Tel Aviv University
3. University of Southern California
Abstract
We experimentally demonstrate a 10-Gbit/s free-space communication link using a single Laguerre-Gaussian (LG) beam with tunable radial and azimuthal modal indices generated by a photonic integrated circuit comprising two concentric uniform circular antenna arrays (UCAs). To tune the azimuthal modal indices ℓ of the generated beam, the azimuthal phase gradient inside each UCA is tuned. To tune the radial mode p of the generated beam, the amplitude ratio and phase difference between the two concentric UCA are tuned. To implement the above functions, the integrated device is composed of (a) two concentric UCAs where the inner (outer) UCA has 4 (8) optical antennas, (b) one Mach-Zehnder interferometer to control the amplitude ratio between the two UCAs, (c) one phase shifter to control the phase distribution between the two UCAs, and (d) phase shifters to control the azimuthal phase gradient of the inner and outer UCA. In our experiment, (a) the two modal indices of the generated beam are independently tuned (ℓ ={0,+1},p={0,1}), (b) the measured mode purity of the generated beam ranges from 23% to 38% among different target LG modes, and (c) a 10-Gbit/s chip-to-free-space optical link carried by the generated tunable LG beam is demonstrated.
Funder
Air Force Research Laboratory
Defense Security Cooperation Agency
Vannevar Bush Faculty Fellowship sponsored by the Basic Research Office of the Assistant Secretary of Defense (ASD) for Research and Engineering (R&E) and funded by the Office of Naval Research
Qualcomm Innovation Fellowship 2020
Airbus Institute for Engineering Research
Office of Naval Research
Air Force Office of Scientific Research