Low-Loss Integrated Photonic Switch Using Subwavelength Patterned Phase Change Material

Efficient integrated photonic switches play a critical role in both interchip optical interconnects and data center networks that need to be dynamically reconfigured. Here, we demonstrate a 1 X 2 switch using phase change material Ge-Sb-Te (GST) combined with a silicon nitride microring resonator. The switch operates by utilizing the dramatic difference in the optical refractive index and extinction coefficient between the crystalline and amorphous phases of GST. By patterning and encapsulating the GST into subwavelength structures, the device achieves a low insertion loss of less than 1 dB in both output ports and can be switched reliably both photothermally and electrothermally.