Ultrahigh Endurance and Extinction Ratio in Programmable Silicon Photonics Based on a Phase Change Material with ITO Heater

Abstract

AbstractPhase‐change‐materials (PCMs) integrated photonics have attracted extensive attention in the field of optical neural networks. However, present PCMs‐integrated photonics are still far from meeting the requirements in real‐world applications due to its unsatisfactory endurance (<3000 cycles) and extinction ratio (ER<20 dB). Here, ultrahigh endurance (>30 000 cycles) and large ER (≥50 dB) are achieved in the photonic device by introducing a trench structure to the indium tin oxide (ITO) heater and utilizing tin‐doped Ge2Sb2Te5 (Sn‐GST) as PCMs. This performance represents a landmark in the PCMs‐integrated photonics, since it solves the problem of poor endurance of ITO heaters and can be comparable to the state‐of the‐art devices in terms of endurance and ER. This excellent endurance and ER stem from the trench structure and high optical contrast PCM of Sn‐GST. Trench structure improves the heating efficiency of the ITO heater and effectively alleviates the thermal stress imposed on the ITO heater, resulting in ultrahigh endurance of the device. Sn‐doping is also beneficial to the endurance and ER improvement, because it can effectively reduce the crystallization temperature and increase the absorption coefficient of the PCM layer. This work provides a new technology for the development of programmable photonics with ultrahigh endurance.