Photonic generation of binary and quaternary phased-coded microwave pulses with tunable frequency multiplication factor

A photonic approach to generate binary and quaternary phase-coded microwave pulses with tunable frequency multiplication factor (FMF) is proposed and demonstrated. By adjusting the input electrical signals, the scheme can generate pulsed radar waveforms with tunable FMF and reconfigurable phase coding pattern. In the scheme, two pairs of orthogonally polarized +/- 2nd-order or +/- 4th-order sidebands are separated into two single sideband signals through an optical sideband separation module. One of the sidebands is then modulated by the coding signal through a dual-drive Mach-Zehnder modulator. By detecting the recombined two sidebands, binary or quaternary phase-coded microwave pulses with FMF of 4 or 8 can be generated. In the simulation experiments, binary and quaternary phase-coded microwave pulses at 20 and 40 GHz are generated. The phase information of the pulses is consistent with the initial coding sequence. Furthermore, the generated phase-coded microwave pulses show great compression capability.