Self-Configuring GHz-Scale Multichannel Silicon Photonic Filter Using a Resonator-Assisted Discrete-Fourier-Transform Interferometer

Abstract

Reconfigurable multichannel optical filters (MOFs) with a high resolution are key devices for high-spectral-efficiency multi-carrier optical transmission systems. However, very few on-chip MOFs reported so far can meet the demands of high spectral resolution, device complexity, and scalable input/output ports. Here, we present a 10 GHz-bandwidth self-configurable silicon MOF using a resonator-assisted discrete-Fourier-transform interferometer. With the help of ultra-low-loss silicon photonic waveguides and low-phase-error Mach–Zehnder switches, the present chip features a low excess loss, low power consumption, high port-count scalability, and sub-GHz spectral resolution. In particular, the present MOF is capable of performing some specific filtering responses with, e.g., near-rectangular or sinc shapes. Furthermore, an efficient self-configuring approach is also developed for the present chip to be programmable, so that different spectral responses can be achieved as desired by automatically optimizing the settings of all the tuning elements, showing great potential for high-capacity optical communication networks.