Ultra-compact wideband filter with sidelobe suppression based on double modulated grating-assisted microring resonator

Abstract

In this paper, we propose an ultra-compact wideband filter (WBF) with high sidelobe suppression. The filter consists of a single microring resonator incorporated with a proposed new structure of double modulated subwavelength gratings. The double modulated subwavelength gratings are obtained via two different fill factors with the same period. The ultra-compact WBF achieved FSR-free, flat response with a 3 dB bandwidth of 1.0734 THz and a sidelobe suppression of 19.79 dB. In addition, a low insertion loss of <0.6 dB and a low in-band ripple of less than 0.2 dB were obtained. The filter has a compact device footprint of 380 µm2.