Image-Rejected Multi-Band Frequency Down-Conversion Based on Photonic Sampling

An image-rejected multi-band frequency down-conversion scheme is proposed and experimentally demonstrated based on photonic sampling. The radio-frequency (RF) signals to be processed are copied into two replicas in quadrature, which then sampled by an ultra-short optical pulse train via a polarization-multiplexed modulator. After polarization demultiplexing detection using pair of low-speed photodetectors, the RF simultaneously down-converted intermediate (IF) band. image components can suppressed quadrature coupling generated IF electrical 90° hybrid coupler (HC). In experiment, range 6 GHz 39 band below 4 local oscillator (LO) signal at 8 generate train. Image rejection achieved digital domain processing compensate for amplitude phase mismatch between implement coupling. addition, through shifter, attenuator, HC achieve signals, also verified analog domain.