Image reject mixer with greatly improved rejection ratio based on the balanced Hartley architecture

A microwave photonic image-reject mixer (IRM) achieving a recorded image rejection ratio (IRR) based on balanced Hartley architecture and an optical pre-filter is proposed and demonstrated. A theoretical model is established to study the influence of the power imbalance and the phase inaccuracy in the balanced Hartley architecture on the IRR. With the assistance of an optical pre-filter, a high IRR can be obtained with moderate amplitude and phase consistencies for the balanced Hartley architecture. A proof-of-concept experiment is carried out. The IRR larger than 90 dB is successfully realized for RF frequencies tuning from 10 to 40 GHz.