Si3N4 ring resonator-based microwave photonic notch filter with an ultrahigh peak rejection

TL;DR

This paper presents a novel microwave photonic notch filter using a Si3N4 ring resonator that achieves record-high peak rejection and tunable bandwidth, enhancing signal processing capabilities in integrated photonic systems.

Contribution

Introduces a simple technique employing a Si3N4 optical ring resonator to achieve ultra-high rejection in microwave photonic filters, surpassing previous integrated filter performances.

Findings

Peak rejection > 60 dB achieved

Tunable bandwidth of 247-840 MHz demonstrated

Notch frequency tuning range of 2-8 GHz achieved

Abstract

We report a simple technique in microwave photonic (MWP) signal processing that allows the use of an optical filter with a shallow notch to exhibit a microwave notch filter with anomalously high rejection level. We implement this technique using a low-loss, tunable Si3N4 optical ring resonator as the optical filter, and achieved an MWP notch filter with an ultra-high peak rejection > 60 dB, a tunable high resolution bandwidth of 247-840 MHz, and notch frequency tuning of 2-8 GHz. To our knowledge, this is a record combined peak rejection and resolution for an integrated MWP filter.