Design requirements for mm-wave integrated optical beamforming networks

Abstract

This paper proposes a mm-wave cellular flexible architecture based on a photonic beamformer network. An overview of integrated optical beamformer technology state-of-the-art is reported considering different implementations, fabrication technologies and the associated design requirements and limitations. A network architecture based on multicore-fiber (MCF) is proposed to operate as fronthaul or backhaul depending on the network configuration and user capacity dynamics. Multi-wavelength operation is achieved employing an optical frequency comb generator capable of providing several phase-correlated optical lines. Following new-radio 5G specifications, both NR 5G frequency ranges (FR) are considered in the proposed network, including FR1 at sub-6 GHz frequency bands, and FR2 in the mm-wave range from 24 to 100 GHz. The work analyses the main subsystems of the integrated photonics beamformer: the laser source which comprises an optical comb, the optical filtering and induced delay subsystems, the arrangement of MCF media to feed different antenna elements and the mm-wave generation subsystem, where optical heterodyning is proposed. The performance of these key subsystems is evaluated experimentally and analyzed by simulation when necessary to assess the proper photonic beamforming network operation.