RESUMO
The conventional concept of radar is based on stand-alone and independent apparatuses. Superior performance is possible, exploiting distributed points of view (i.e., distributed radars) and centralized data fusion, but systems based only on radio-frequency technology are not able to guarantee the requested degree of coherence and high capacity links among radars. In the current distributed systems, radars act almost independently from each other. Thus, data fusion, which must be performed on locally pre-processed information, can only exploit partial information content, harming the imaging capability of the distributed system. Here we present, to the best of our knowledge, the first extended analysis and experiment of a distributed coherent multiple input-multiple output radar system, enabled by photonics, which maximizes the information content extracted by a centralized data fusion, providing unprecedented resolution capabilities. Stepping from previous achievements, where photonics has been demonstrated in single radars, here photonics is used also for providing coherence and high capacity links among radars. The numerical analysis also demonstrated the benefits of coherent multi-band operation for sidelobe reduction, i.e., false alarms reduction.
RESUMO
An innovative and effective architecture for lidar systems is presented and experimentally demonstrated. The proposed scheme can also be easily exploited for optical communications. In particular, the system includes an innovative lidar software-defined architecture based on optically coherent detection, overcoming current drawbacks of time of flight incoherent systems. The experiments demonstrate the ability to perform long range detection resorting to the waveform compression on the continuous wave approach, obtaining a range resolution of 15 cm with a sensitivity of -95 dBm. Beside the bulk implementation, the system has been also implemented in a photonic integrated circuit using complementary metal-oxide-semiconductor-compatible silicon on insulator technology with an extremely reduced footprint of 1.5 mm×3.5 mm. The testing of the integrated device confirms the effectiveness of this proof-of-concept realization.