Photonic crystals (PCs), consisting of a periodic pattern of variations in the material properties, are one of the platforms proposed as "synthetic" optical materials to meet the need for optical materials with desired properties. Recently, applications based on dispersive properties of the PCs have been proposed in which PCs are envisioned as optical materials with controllable dispersive properties. Unlike the conventional use of PCs to achieve localization, in these new applications propagation inside the photonic crystal is studied, and their dispersive properties are utilized. Among these applications, the possibility of demultiplexing light using the superprism effect is of particular interest.

Possibility of integration and compactness are two main advantages of PC-based wavelength demultiplexers compared to other demultiplexing techniques, for applications including compact spectrometers (for sensing applications), demultiplexers (for communications), and spectral analysis (for information processing systems). I develop the necessary simulation tools to study the dispersive properties of photonic crystals. In particular, I will focus on superprism-based demultiplexing in PCs, and define a phenomenological model to describe different effects in these structures and to study important parameters and trends. A systematic method for the optimization and design of these structures is presented. Implementation of these structures is experimentally demonstrated using the devices fabricated in a planar SOI platform based on designed parameters. In the next step, different approaches to improve the performance of these devices (for better resolution and lower insertion loss) are studied, and extension of the concepts to other material platforms is discussed.