Tunable Bandpass Filter With Serially Coupled Ring Resonators Assisted MZI

We present the analytical modelling and experimental characterization of a new design of silicon nitride tunable bandpass filter based on serially coupled ring resonators assisted Mach-Zehnder interferometer (SR-MZI). SR-MZI filters provide an additional degree of freedom to independently control the bandwidth and shape of the passband as compared to previous ring-assisted MZI filters. It is possible to tune the bandwidth, shape and side-band rejection of the response by adjusting the coupling in the filters, providing a scope for fully reconfigurable performance. The fabrication of the filters is CMOS compatible and supports mass production. Preliminary results for thermal controllability are presented.