Patent ID: 7110641

Claim:
A device for directional and wavelength-selective optical coupling between two waveguides, the device being characterized in that it comprises a plane component ( 10 ) of photonic crystal structure constituted by a plurality of periodically distributed elements ( 20 ), the component having two parallel waveguides ( 14 , 16 ) separated by a coupling zone ( 18 ), the coupling zone being formed by parallel and adjacent rows of said periodically distributed elements ( 20 ) and the waveguides ( 14 , 16 ) being formed by parallel and adjacent rows lacking said periodically distributed elements ( 20 ) or being formed by such elements having dimensions, positions, or refractive index that have been substantially modified, the longitudinal edges of the waveguides having a periodic structure serving, for determined frequencies, firstly to provide local coupling between a guided mode in one of the waveguides ( 14 ) and a higher order mode of said waveguide, and secondly to provide coupling between said higher order mode and a higher order mode of the other waveguide ( 16 ) through the coupling zone ( 18 ) and coupling between the higher order mode of the other waveguide ( 16 ) and the guided mode of said other waveguide, whereby said frequencies can be extracted from a guided signal in the first waveguide ( 14 ) and injected into the other waveguide ( 16 ), said frequencies being those that are not transmitted in the first waveguide, each waveguide ( 14 , 16 ) of the component ( 10 ) being connected at its ends to an inlet waveguide ( 22 , 24 ) and to an outlet waveguide ( 26 , 28 ), the inlet and outlet waveguides ( 22 , 24 , 26 , 28 ) being of photonic crystal structure and having structural characteristics different from those of said waveguides ( 14 , 16 ).