Nonvolatile programmable silicon photonics using an ultralow-loss Sb<sub>2</sub>Se<sub>3</sub> phase change material.

Delaney, Matthew; Zeimpekis, Ioannis; Du, Han; Yan, Xingzhao; Banakar, Mehdi; Thomson, David J; Hewak, Daniel W; Muskens, Otto L · Sci Adv · 2021

basic_science · Level V

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Abstract

The next generation of silicon-based photonic processors and neural and quantum networks need to be adaptable, reconfigurable, and programmable. Phase change technology offers proven nonvolatile electronic programmability; however, the materials used to date have shown prohibitively high optical losses, which are incompatible with integrated photonic platforms. Here, we demonstrate the capability of the previously unexplored material Sb<sub>2</sub>Se<sub>3</sub> for ultralow-loss programmable silicon photonics. The favorable combination of large refractive index contrast and ultralow losses seen in Sb<sub>2</sub>Se<sub>3</sub> facilitates an unprecedented optical phase control exceeding 10π radians in a Mach-Zehnder interferometer. To demonstrate full control over the flow of light, we introduce nanophotonic digital patterning as a previously unexplored conceptual approach with a footprint orders of magnitude smaller than state-of-the-art interferometer meshes. Our approach enables a wealth of possibilities in high-density reconfiguration of optical functionalities on silicon chip.