Field-Programmable Microwave Photonic Filter for Interference-Suppressing RF Communications

The escalating complexity of next-generation wireless systems demands advanced interference suppression beyond the low-frequency band. While integrated microwave photonic filters (IMPFs) offer a solution, existing application-specific (AS) photonic integrated circuits (PICs) lack programmability and require costly redesigns. Inspired by the hardware flexibility of field-programmable gate arrays (FPGAs), this work demonstrates a field-programmable hexagonal mesh PIC that enables software-defined reconfiguration of microwave photonic filters (MPFs). By programming voltages across tunable basic units (TBUs), the IMPF achieves a dynamic tuning of notch frequency (132 GHz), with a rejection ratio (RR) of 27.28 dB, and a 3-dB bandwidth of 0.4 GHz. Experimental validation in 2-Gb/s quadrature phase shift keying (QPSK) communications shows >40% error vector magnitude (EVM) improvement under strong interference, outperforming state-of-the-art ASICs. This platform bridges photonic integration with functional adaptability, providing a scalable foundation for future radio frequency (RF) systems.