Mid‐infrared integrated photonics on silicon: a perspective

Abstract The emergence of silicon photonics over the past two decades has established silicon as a preferred substrate platform for photonic integration. While most silicon‐based photonic components have so far been realized in the near‐infrared (near‐IR) telecommunication bands, the mid‐infrared (mid‐IR, 2–20‐μm wavelength) band presents a significant growth opportunity for integrated photonics. In this review, we offer our perspective on the burgeoning field of mid‐IR integrated photonics on silicon. A comprehensive survey on the state‐of‐the‐art of key photonic devices such as waveguides, light sources, modulators, and detectors is presented. Furthermore, on‐chip spectroscopic chemical sensing is quantitatively analyzed as an example of mid‐IR photonic system integration based on these basic building blocks, and the constituent component choices are discussed and contrasted in the context of system performance and integration technologies.