Silicon-on-Insulator Dual-Ring Notch Filter for Optical Sideband Suppression and Spectral Characterization

A new optical single-sideband (OSSB) modulation technique for wideband microwave photonic applications is presented. It is based on an integrated silicon-on-insulator dual-ring structure that exhibits weak electromagnetically induced transparency-like notch filter characteristics. Experimental results demonstrate optical sideband suppression of more than 29 dB for signals over 17-35 GHz with an achievable suppression as high as 40 dB. The OSSB structure is highly effective in suppressing dispersion penalties in microwave fiber transmission, with results showing a reduction in the electrical power ripple to less than +/- 1.5 dB for RF frequencies up to 30 GHz. The OSSB structure also enables new applications in optical vector network analyzers for optical component characterization, demonstrating the ability to measure both the amplitude and phase responses of a high-resolution ultranarrow filter based on stimulated Brillouin scattering, and also to perform wideband measurements over 10-30 GHz, offering an integrated approach for OSSB modulation that is compatible with silicon-based on-chip microwave photonic signal processing systems.