On-chip Brillouin filtering of RF and Optical Signals

High-resolution signal processing will be key in current and future communication networks in crowded spectral environments. Signal processing based on the nonlinear optical process known as stimulated Brillouin scattering (SBS) are applicable in high-performance analog signal filtering for RF communications and in coherent optical communication systems for carrier amplification. To meet the requirements of small size, low weight and low power, the development of chip-based devices is critical. In this paper, we present an overview of on-chip SBS demonstrations of RF bandpass and bandstop filter functionalities with large frequency tuning and reconfigurability from tens of MHz to almost 0.5 GHz, applicable in RF communications. We also present our recent results on chip-based SBS filtering for optical communications. While traditionally, SBS has been deemed to be incompatible with phase-sensitive communications, these latest results highlight the viability of SBS-enhanced high-capacity digital communication networks. We finally discuss the limitations of SBS filtering and also present some strategies to overcome them.