Liquid crystal microdroplet holograms for waveguide WDM applications

Mechanisms of index control and dynamic gratings for single mode waveguides are reviewed. Electronically switchable Bragg gratings (ESBG) based on holographic polymerized polymer/liquid crystal composites stand out as a promising material for waveguide and fiber optic applications with large index modulations, low intrinsic scattering, adequate switching speeds, and low cost grating formation. This combination of properties is not shared by semiconductors, electro-optic crystals or polymers, or bulk liquid crystal films.