Optical device with superimposed photonic circuits for coupling to one or more optical waveguides
Optical device with superimposed photonic circuits, for coupling to an optical waveguide. Said device comprises a substrate ( 44 ) and, on said substrate, an integrated photonic circuit ( 46 ) adapted to be coupled to at least one optical waveguide ( 48 ) which transmits a light signal ( 50 ) and for processing said signal. According to the invention, the circuit comprises two superimposed elementary integrated photonic circuits ( 52, 54 ), each of which is adapted to be coupled to a given polarization state of the signal and to process this state. The invention applies particularly to optical telecommunications.
1. An optical device comprising:
a substrate and,
on said substrate, an integrated photonic circuit adapted to be optically coupled to at least one optical waveguide to transmit a light signal and further adapted for processing the light signal, wherein the integrated photonic circuit comprises first and second elementary integrated photonic circuits which are superimposed, the first and second elementary integrated photonic circuits being adapted to, respectively, be coupled to first and second given polarisation states of the light signal and for processing said given first and second polarisation states, respectively, and wherein each of the first and second elementary integrated photonic circuits includes a coupling part which is adapted to be coupled to the optical waveguide, and the respective coupling parts of the first and second elementary integrated photonic circuits are superimposed.
2. An optical device according to claim 1 , wherein the second elementary integrated photonic circuit is between the substrate and the first elementary integrated photonic circuit, the first elementary integrated photonic circuit being configured to receive the light signal and adapted to be coupled to a first polarisation state of the light signal, the second elementary integrated photonic circuit being adapted to be coupled to a second polarisation state of the light signal.
3. An optical device according to claim 1 , wherein the first and second elementary integrated photonic circuits are nanophotonic circuits.
4. An optical device according to claim 1 , wherein the coupling part of each of the first and second elementary integrated photonic circuits is adapted to be coupled to the corresponding given polarisation state of the light signal, and each of the first and second elementary integrated photonic circuits further includes a part for processing the given polarisation state of the light signal thus coupled.
5. An optical device according to claim 4 , wherein the second elementary integrated photonic circuit is between the substrate and the first elementary integrated photonic circuit, the first elementary integrated photonic circuit being configured to receive the light signal and adapted to be coupled to a first polarisation state of the light signal, the second elementary integrated photonic circuit being adapted to be coupled to a second polarisation state of the light signal and wherein the coupling part of the first elementary integrated photonic circuit is adapted to be coupled to the first polarisation state of the light signal, and the coupling part of the second elementary integrated photonic circuit is adapted to be coupled to the second polarisation state of the light signal.
6. An optical device according to claim 4 , wherein each coupling part includes a one dimensional diffraction grating.
7. An optical device according to claim 6 , wherein each of the one dimensional diffraction gratings comprises parallel lines and the lines of one of the one dimensional diffraction gratings are parallel to the lines of the other one dimensional diffraction grating.
8. An optical device according to claim 6 , wherein each of the one dimensional diffraction gratings comprises parallel lines and the lines of one of the one dimensional diffraction gratings are perpendicular to the lines of the other one dimensional diffraction grating.
9. An optical device according to claim 4 , wherein each coupling part includes a diffraction grating chosen among gratings with curved patterns, gratings with variable pitch from one pattern to the next, photonic gratings and diffractive optics.
10. An optical device according to claim 4 , further comprising a light reflecting structure, placed below the set of superimposed coupling parts.
11. An optical device according to claim 1 , further comprising a photodetector adapted to detect the first and second polarisation states which are respectively processed by the first and second elementary integrated photonic circuits.
12. An optical device according to claim 1 , wherein said optical waveguide is an optical fiber.