Recent Progress on Waveguide-Based Phase-Change Photonic Storage Memory

Abstract

Memory targeted for data storage plays a key role in determining the operational performances of the modern digital computer, particularly in the age of ‘big data.’ Conventional computer memory devices are usually made of complementary-metal-oxide-semiconductors (CMOS). Along with the increase of the integration density, the distance between neighboring CMOS components is further reduced, consequently accompanied with some adverse effects such as relatively low transmission speed and severe disturbances. To address these issues, an innovative photonic memory that combines phase-change materials with silicon-based waveguides has recently attained tremendous attention owing to its ability to store and process data in a photonic manner. Triggered by this novel concept, a plasmonic-based phase-change integrated memory was subsequently proposed, which allows for similar properties to the waveguide-based memory but with higher integration density. In spite of these progress, a comprehensive review related to the operational principle of these emerging memories, their current status, and the prospect envisage is still missing. To help researchers better understand the performances superiorities of the phase-change photonic memory, in this review we first present the physical properties of the phase-change materials, and subsequently introduce the operational principles of different phase-change photonic memories such as waveguide-based memory and plasmonic-based memory. The current status of these memories is also elaborated, followed by the detailed analysis of their respective performance pros and cons. The developing prospect of the phase-change photonic memories are finally envisaged.