Tunable optical filter using second-order micro-ring resonator

In this paper, we design and fabricate a silicon integrated optical filter consisting of two cascaded micro-ring resonators and two straight waveguides. Two micro-heaters are fabricated on the top of two micro-rings respectively, which are employed to modulate the micro-rings to perform the function of a tunable optical filter by the thermo-optic effect. The static response test indicates that the extinction ratio and 3-dB bandwidth are 29.01 dB and 0.21 nm respectively, the dynamic response test indicates that the 10%-90% rise and 90%-10% fall time of the filter are 16 mu s and 12 mu s, respectively, which can meet the requirements of optical communication and information processing. Finally, the power consumption of the device is also characterized, and the total power consumption is about 9.43 mW/nm, which has been improved efficiently.