Integrated Photonic Chip Enabled Simultaneous Multichannel Wideband Radio Frequency Spectrum Analyzer

Radio frequency (RF) spectrum analysis is an essential technique for monitoring signal quality in ultrahigh-speed optical transmission, broad bandwidth photonic RF arbitrary waveform generation, and for characterization of high repetition rate optical pulse sources. Whereas the intrinsic bandwidth of electronics limits its use for RF spectrum measurement of high-speed signals, a photonic approach based on ultrafast Kerr nonlinear effects can readily measure the RF spectrum of optical signals having a bandwidth beyond 1 THz. The majority of fiber-based or integrated photonic RF spectrum analyzers reported to date can monitor only one channel at a time. We demonstrate how to harness mode-selective excitation of nonlinear optical effects to perform simultaneous multichannel RF spectrum analysis using a single integrated silicon photonic device. This approach, which can be scaled to a higher number of channels, opens up a new degree of freedom for realizing multichannel signal characterization using a single integrated photonic device.