Optically beamformed array performance

Free-space optical beamforming networks (OBFN) show great potential for wideband antenna arrays. However, for a practical implementation, several technological and architectural issues need to be addressed. This paper models an existing OBFN architecture in reception mode and studies its impact in the performance of a real SAR system in terms of noise figure (NF), output third-order intermodulation products (IP3) and dynamic range (SFDR). Once the impact of the OBFN has been studied, different improvements are introduced like the use of erbiumdoped fiber amplifiers (EDFAs), avalanche photodetectors (APDs), RF phase shifters and RF power amplifiers, leading to a solution suitable for large arrays. Furthermore, different system design trade-offs (RF and optical) are considered.