Comparison of the phase change process in a GST-loaded silicon waveguide and MMI

Abstract

In the past decades, silicon photonic integrated circuits (PICs) have been considered as a promising approach to solve the bandwidth bottleneck in optical communications and interconnections. Despite significant advances, large-scale PICs still face a series of technical challenges, such as footprint, power consumption, and routing state storage, resulting from the active tuning methods used to control the optical waves. These challenges can be partially addressed by combining chalcogenide phase change materials (PCMs) such as Ge2Sb2Te5 (GST) with silicon photonics, especially applicable in switching applications due to the nonvolatile nature of the GST. Although GST phase transitions between amorphous and crystalline states actuated by optical and electrical pulses heating have been experimentally demonstrated, there is no direct comparison between them. We carried out simulations and experiments to systematically investigate the difference in the phase change process induced by optical and electrical pulses for two types of Si-GST hybrid waveguides. For the phase transition induced by optical pulses, the device has a clear advantage in terms of power consumption and operation speed. For the phase transition induced by electrical pulses, the device is suitable for large-scale integration because it does not require complex light routing. It helps us better understand the phase change process and push forward the further development of Si-GST hybrid integration platform, bringing in new potential applications.

On-Chip Integrated Photonic Devices Based on Phase Change Materials

“…On the topic of comparison between electrical switching and optical switching in GST-based silicon photonic switches, Zhang concluded that, for the amorphization process, optical switching is advantageous in terms of speed and energy efficiency. However, as alluded to earlier, for large-scale integration purposes, electrical switching is still advantageous as it does not require a complex routing circuit for the photonic circuit [101].…”

Space and Time Modulations of Light with Metasurfaces: Recent Progress and Future Prospects

“… a The energy densities and switching speeds were found to strongly depend on the design and switching mechanism (optical or electrical), as well as on the preparation methods and deposition conditions, refs − . The values reported here should therefore not be seen as fundamental ones, but rather as state-of-the-art metrics that we collected from different works − that we find representative of the different values reported in the literature. …”

Full Control of Fano Spectral Profile with GST-Based Metamaterial

“…For q = −5.6, the narrowband absorption with absorption coefficient A = 0.94 (reflection coefficient R = 0.02) and prominent Q = 190 promises a high Q switching (Figure 4b). To implement the switching in the modern photonic platform, one can integrate thermal control components 35 or optical/electrical excitation optical circuits 36 to the Fano resonator, which are common routes to modulate GST phase transition in silicon photonics. 37 Proper optical imaging setup helps to visualize the effect of optical switching from high Q absorption to high Q reflection.…”