Photonic generation of microwave binary modulation signals with high frequency multiplication factors

An approach for photonic generation of binary modulation microwave signals with high frequency multiplication factors is proposed and investigated. The key components are a polarization division multiplexing (PDM) dual parallel Mach–Zehnder modulator (DPMZM) and a polarization modulator (PolM). The PDM-DPMZM is employed to produce two orthogonally polarized lightwaves with their polarization directions aligned with the two principle axes of the following PolM. Then the two lightwaves are sent into the PolM for complementary phase coding. A theoretical analysis and a simulation work are performed to demonstrate the generation of microwave amplitude shift keying (ASK) signal with frequency multiplication factor of eight, frequency shift keying (FSK) signal with frequency multiplication factors of four/eight and phase shift keying (PSK) signal with frequency multiplication factor of four. The modulation format can be switched simply by adjusting the system parameters without revising the structure. In addition, the bit rate and the carrier frequency can be tuned flexibly and independently, and good frequency tunability is realized.