Multifunctional microwave signal generation and processing based on equivalent phase modulation

A photonic-based approach for multifunctional microwave signal generation and processing is demonstrated based on equivalent phase modulation. The key component of the system is a dual-polarization quadrature phase-shift keying (DPQPSK) modulator. One dual-parallel Mach-Zehnder modulator (DP-MZM) in the DP-QPSK modulator is biased to function as an equivalent phase modulator (e-PM), while the other DP-MZM is biased as a carrier-suppressed singlesideband (CS-SSB) modulator. The two optical signals from the two DP-MZMs are combined and detected in a photodetector. With different driving signals applied to the two DP-MZMs, different functions can be achieved. When the e-PM is driven by a direct current signal to phase shift the optical carrier, and the CS-SSB modulator is to generate a first-order optical sideband of the driving RF signal, a wideband microwave phase shifter is implemented, which can introduce arbitrary phase shift to the electrical driven signal applied to the CS-SSB modulator. Under the above condition, if the CS-SSB modulator is to generator a first-order and an opposite third-order optical sidebands of the driving RF signal, a repetition rate tunable triangular and square waveform generation scheme can be realized. When the e-PM is driving by an electrical coding signal, and the CS-SSB modulator is to generate a first-order optical sideband of the driving RF signal, a reconfigurable pulse compression signal generator is achieved. Experimental verifications are made to demonstrate the multifunctional system, which has the potential to be used in a variety of microwave systems.