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

1. 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.

2. The apparatus as claimed in claim 1 , wherein the first phase plate is longitudinally displaceable perpendicular to a propagation direction of the signal in the second free-beam region.

3. The apparatus as claimed in claim 1 , wherein the first phase plate is moveably arranged in a groove in a planar substrate on which the second free-beam region is implemented.

4. The apparatus as claimed in claim 1 , wherein the first phase plate effects a spatially dependent modification of the phase of the spatially separated spectral components of the signal, which modification has a cubic characteristic that is dependent upon a location at which the spatially separated spectral components strike the first phase plate.

5. The apparatus as claimed in claim 1 , further comprising means for displacing the first phase plate in the second free-beam region.

6. The apparatus as claimed in claim 1 , wherein the means for spatially dependent modification of the phase of the spatially separated spectral components comprise an additional phase modification device that is fixedly arranged in the second free-beam region.

7. The apparatus as claimed in claim 6 , wherein the additional phase modification device effects a spatially dependent shifting of a phase of the spatially separated spectral components of the signal in such a way as to compensate-a wavelength dependency of the chromatic dispersion set by means of the first phase plate.

8. The apparatus as claimed in claim 6 , wherein the additional phase modification device effects a spatially dependent shifting of the phase of the spatially separated spectral components of a signal in such a way as to compensate an intrinsic dispersion of the apparatus.

9. The apparatus as claimed in claim 6 , wherein the additional phase modification device effects a spatially dependent modification of the phase of the spatially separated spectral components of the signal, which modification has a cubic characteristic dependent on a location at which the spatially separated spectral components strike the additional phase modification device.

10. The apparatus as claimed in claim 6 , wherein the additional phase modification device comprises a second phase plate, which is arranged non-displaceably in the second free-beam region.

11. The apparatus as claimed in claim 10 , wherein the second phase plate is arranged in a groove in a planar substrate on which the second free-beam region is implemented.

12. The apparatus as claimed in claim 10 , wherein the second phase plate consists of silicon.

13. The apparatus as claimed in claim 12 , wherein the second phase plate includes an antireflection coating.

14. The apparatus as claimed in claim 1 , wherein the apparatus is of symmetrical design, and the first phase plate is located in a central zone of the second free-beam region between the first and the second phase gratings.

15. The apparatus as claimed in claim 14 , wherein the means for spatially dependent modification of the phase of the spatially separated spectral components comprises an additional phase modification device that is fixedly arranged in the second free-beam region, and wherein the additional phase modification device is also arranged in the central zone of the second free-beam region between the first and the second phase gratings.

16. The apparatus as claimed in claim 1 , wherein the waveguide input structure and the waveguide output structure are implemented by a single waveguide structure, the first free-beam region and the third free-beam region are implemented by a single free-beam region, and the first phase grating and the second phase grating are implemented by a single phase grating, and in which the second free-beam region has a reflection device at which the optical signal is reflected.

17. The apparatus as claimed in claim 16 , wherein the reflection device is formed by a mirror constructed in the second free-beam region.

18. The apparatus as claimed in claim 16 , wherein the waveguide input/output structure is connected to a three-gate circulator.

19. The apparatus as claimed in claim 1 , wherein the planar optical apparatus comprises SiO 2 on Si.

20. The apparatus as claimed in claim 1 , wherein the first phase plate consists of silicon.

21. The apparatus as claimed in claim 20 , wherein the first phase plate includes an antireflection coating.