Thermal dynamics of phase switching process of an SOI rib waveguide covered with a Ge2Sb2Te5 phase change material film

The combination of phase-change materials (PCMs) and integrated photonics promotes the development of new forms of all-optical devices and potentially provides large-scale all-optical arithmetic-logic units and neuromorphic processing chips using the large contrast in optical properties when switched between amorphous and crystalline phase states. Therefore, a proper understanding of the refractive index fluctuations during phases-witching is essential for controlled and optimized device operation. We present analytical results to simulate the temperature-field distribution while an optical pulse is injected into a waveguide with a phase change material cell. These results demonstrate good agreement with the calculations by the finite element method. Furthermore, the crystallization fraction and refractive index change of the Ge2Sb2Te5 PCM cell are investigated in calculation, along with the attenuation effect of the SOI rib waveguide during the phase switching and the dependence on the optical injection. Therefore, it is necessary to set the optical pulses appropriately for the phase-switching process for particular devices, such as optical memory and photonics neurons.

Automated summary

The combination of phase-change materials and integrated photonics allows for the development of new all-optical devices. Understanding the fluctuations in refractive index during phase-switching is crucial for optimal device operation. Simulation results show good agreement with calculations, and the crystallization fraction and refractive index change of the PCM cell are investigated. Proper setting of optical pulses is necessary for specific devices.