Dielectric cavities support record low mode volumes by incorporating subwavelength features into photonic crystal unit cells.

Optical phase change materials (O-PCMs) are being explored for a variety of photonic applications due to the extraordinarily large changes in optical properties that occur during electronic and/or structural phase transitions. Here, recent work integrating O-PCMs in integrated silicon photonic devices is presented. Conceptually proposed and experimentally realized thermo-optic, electro-optic, and all-optical Si/O-PCM devices are described and perspectives on the potential for Si/O-PCM electro-optic and all-optical modulators are outlined.