Reconfigurable multi-band transceiver with RF self-interference cancellation and image rejection based on OFC

A photonic-assisted multi-band transceiver with self-interference cancellation (SIC) and image rejection (IR) capabilities is proposed based on dual-drive dual-parallel Mach-Zehnder modulators (DD-DPMZM) and a 90° optical hybrid. By matching the power and delay of the self-interference (SI) signal generated during in-band full-duplex communication with the reference signal in the other sub-Mach-Zehnder modulator of the DD-DPMZM, the SI signal can be directly canceled in the optical domain. Moreover, the image signal (IM) is suppressed via phase cancellation in the 90° optical hybrid. The system uses an optical frequency comb (OFC) as a multi-frequency optical local oscillator and reconfigures the wavelength-selective switch) to flexibly select the OFC comb teeth. By combining these two technologies, the RF signal can be up-converted and down-converted across multiple frequency bands, ranging from the C-band to the Ka-band. Since the system does not rely on optical filters or wavelength division multiplexing devices and imposes no restrictions on the operating frequency of the output signal, it demonstrates strong tunability. The SIC and IR performance of the transceiver was evaluated through theoretical analysis and simulation. The results show that the proposed scheme can effectively suppress both SI and IM under various signal bandwidth and power conditions. When the signal of interest is a 4-quadrature amplitude modulation signal with a bandwidth of 0.5 GHz, the SIC depth of the mixed signal exceeds 40.2 dB, the image rejection ratio exceeds 38.4 dB, and the error vector magnitude is reduced to below 3.5%. The system demonstrates good capabilities for multi-band frequency conversion and recovery of the RF signal from SI and IM signals.