Chip-based broadband microwave photonic mixer with image rejection

Microwave photonics has shown it can efficiently down-convert broadband signals while exploiting good image rejection and can operate over a wide frequency range. Although impressive, existing approaches that rely on bulky fibre implementations lack the size and performance requirements for many applications. On-chip integration can improve the size, weight, and performance, however, no photonic frequency mixer has combined broadband image rejection with on-chip integration. Here, we demonstrate the first broadband integrated microwave photonic mixer with deep image rejection and -1dB conversion gain. Stimulated Brillouin scattering is used to select the desired RF signal and RF interferometry is used to further suppress the image component. By broadening the Brillouin pump, we down-convert multiple carrier signals (11 GHz and 12 GHz) with bandwidths of 400MHz and 100 MHz while achieving 16 dB and 28.5 dB of broadband image rejection, respectively.