Ultra-Compact Tuneable Notch Filter Using Silicon Photonic Crystal Ring Resonator

A novel ultra-compact photonic tuneable notch filter with large bandwidth, high extinction ratio, fast response, and flat stopband is modeled and designed. It consists of a silicon-based ring resonator with one-dimensional photonic crystal superimposed onto a ring portion. Engineering the defects into the photonic crystal section allows to achieve the equalization of the bottom band of the filter response. Large bandwidth (B = 10.43 GHz) and high extinction ratio (ER = 41 dB) have been attained with a frequency response of the first-order Butterworth filter type. Continuous and wide range tunability of the central frequency (15 GHz) has been obtained by using the carrier injection technique, together with fast reconfigurability (≈1 ns) and power consumption of 47 mW. The device footprint is as very small as about 150 μm2. This performance makes the proposed device suitable for several filtering applications, such as wireless networks (5G) and telecommunication reconfigurable payloads in Telecom and Space scenario, respectively.