Multi-Band RF Transceiver Based on the Polarization Multiplexed Photonic LOs and Mixers

A photonics-based multi-band RF transceiver is proposed and demonstrated. Both for the multi-band transmitter and receiver sections, the polarization multiplexed photonic LO unit is shared, and the dual-polarization photonic mixer modules with similar structures are introduced. The architectural complexity is reduced, bringing benefits to the reliability, dimensions, and cost of the system. Based on the same transceiver, RF signals in four bands can be simultaneously generated, and the RF echoes can be processed to the same IF band with the interference effectively suppressed. The strict requirements with either the photonic or the electrical filters are avoided. Furthermore, the generation and processing capability can be extended to being with 4N RF signals by introducing a polarization orthogonal optical frequency comb (OFC). The proposed architecture is therefore promising for the future cognitive radar systems which need to work in multiple bands and have a variety of functions to learn, infer, and react to the environment. A proof-of-concept experiment is taken. Four RF signals covering X, Ku, K and Ka bands with 1-GHz instantaneous bandwidth are simultaneously generated and processed. More than 26-dB crosstalk suppression ratio is realized for the four bands. The ranging operated in K- and Ka-bands simultaneously are also implemented.