Wavelength-selective nonvolatile optical switch based on periodic Ge₂Sb₂Se₄Te₁-assisted racetrack micro-ring

Abstract Integrated silicon photonics based on phase-change materials have the advantages of energy efficiency, ultra-compactness, and nonvolatility, with a promising prospect in reconfigurable photonic systems. A wavelength-selective 1 × 2 nonvolatile optical switch based on a periodic Ge 2 Sb 2 Se 4 Te 1 (GSST)-assisted racetrack silicon micro-ring is proposed, where the GSST is embedded in the micro-ring as a one-dimensional photonic crystal. The switch state changes from ‘OFF’ to ‘ON’ by changing the GSST state from amorphous to crystal. The results show that the extinction ratio of the device is 27.99 dB and 19.57 dB at the drop and through ports, respectively. The insertion loss is as low as 1.21 dB at the through port in the crystal state and 0.61 dB at the drop port in the amorphous state. The proposed on-chip optical switch significantly enhances device integration, offers a potential path toward the development of nonvolatile Si-GSST hybrid optical switches, and is crucial to realizing reconfigurable photonic systems. Furthermore, the resonant wavelength of the switch changes very little, by only 0.66 nm between the ‘ON’ and ‘OFF’ states, which is suitable for multichannel wavelength-division-multiplexing systems.