Flexible integrated photonics: where materials, mechanics and optics meet [Invited]

While the vast majority of integrated photonic devices are traditionally fabricated on rigid substrates, photonic integration of both passive and active photonic devices on flexible polymer substrates has been demonstrated in recent years, and its applications in imaging, sensing and optical interconnects are being actively pursued. This paper presents an overview of the emerging field of mechanically flexible photonics, where we examine material processing and mechanical design rationales dictated by application-specific optical functionalities. The examples include semiconductor nanomembranes which serve as the key enabling material for hybrid inorganic-organic flexible active photonics, and monolithically integrated passive photonic structures fabricated from semiconductors, polymers, or amorphous materials. Technical challenges and further research opportunities related to materials engineering and device integration on flexible substrates are also discussed.