Planar optical apparatus for setting the chromatic dispersion in an optical system

A planar optical apparatus for setting the chromatic dispersion in an optical system, comprising:

• a waveguide input structure with a first free-beam region for transmitting a signal,
• a first phase grating, connected to the first free-beam region, for spatially separating the spectral components of the signal,
• a second free-beam region, connected to the first phase grating, for receiving the spatially separated spectral components of the signal,
• means for performing spatially dependent modification of a phase of the spatially separated spectral components of the signal in the second free-beam region,
• a second phase grating, connected to the second free-beam region, for combining the phase-modified spectral components of the signal, and
• a waveguide output structure with a third free-beam region attached to the second phase grating for transmitting the phase-modified signal,
• wherein the means for spatially dependent modification of the phase of the spatially separated spectral components includes a first phase plate that is moveably disposed in the second free-beam region.