Abstract
This paper reviews the application of photonic crystals (PhCs) and related periodic structures to spectrometers and wavelength filters. In the first half of the paper in-plane type spectrometers utilizing superprism effect are reviewed. In the latter half out-of-plane and surface-normal type devices, where guided mode resonance (GMR) plays a center role, are described. Finally, Bragg reflection type wavelength filters are dealt with.