Design and Performance Optimization of a Nonvolatile Silicon Photonic Switch Using GST-Integrated Concentric Microring Resonators

This study presents a silicon-based concentric ring optical switch utilizing Ge2Sb2Te5 (GST) phase-change material. The device featured a double-ring resonator structure with an outer ring radius of 5 μm, an inner ring radius of 4.2 μm, and a waveguide width of 400 nm. Through optimization of the coupling gap (210 nm) and GST coverage (8 segments), the device achieved high-performance optical switching functionality at the 1550 nm wavelength, exhibiting a high extinction ratio of 26.4 dB in the amorphous state and a low insertion loss of 0.95 dB in the crystalline state. Comparative analysis revealed significant advantages over conventional silicon-based optical switches: (1) Non-volatile operation enabled by GST phase transition eliminates the need for continuous power supply after switching; (2) High refractive index contrast (Δn > 2) ensures strong optical modulation; (3) Compact structure (5 μm outer radius) facilitates high-density integration. Furthermore, compared to devices using GSST material, the GST-based design showed a 12 dB improvement in extinction ratio and a 1.76 dB reduction in insertion loss. This research presents a novel approach to developing high-performance, low-power photonic integrated devices.