All-optical switch based on novel physics effects

All-optical switches are among the most important parts of integrated photonics. Ultrahigh speed and ultralow energy consumption are two necessary indexes of all-optical switches. Traditionally, all-optical switches are based on concepts such as micro-ring resonators, surface plasmon polaritons, photonic crystals, and metamaterials. However, such platforms cannot satisfy the demand for high performance of all-optical switches. To overcome the limited response time and energy consumption, recent studies have introduced new applications of such physics as parity–time symmetry, exceptional points, topological insulators, and bound states in a continuum. Such physical concepts not only provide promising research avenues for the all-optical switch but also broaden the design channel. This is expected to achieve ultracompact, ultrafast, and high-capacity all-optical information processing.