Optical coupling device for a photonic circuit
AssigneeCommissariat A L'energie Atomique Et Aux Energies Alternatives
InventorsKarim HASSAN, Salim BOUTAMI, Sylvie MENEZO
Life of this patent
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Abstract
A coupling device including, integrated in or on a substrate, a waveguide capable of guiding a light beam centred on a central wavelength λ0 and an optical coupler. The waveguide and the optical coupler extend in two superposed stages of the coupling device. The optical coupler is composed of at least one index gradient structure. The average optical index in the index gradient structure varies monotonously, decreasing with increasing distance from the waveguide, the average optical index being an average value of the optical index in a cubic volume with a side dimension equal to: λ 0 2 * n eff in which neff is the effective index of guided mode in the waveguide.
Claims15
A coupling device comprising a substrate in or on which the following are integrated:
- a waveguide capable of guiding a light beam centred on a central wavelength λ0;
- and
- an optical injection and/or extraction coupler;
- a guide stage comprising the waveguide and a coupling stage comprising the optical coupler, superposed one on the other, wherein the optical coupler is composed of at least one index gradient structure, and wherein the average optical index in the index gradient structure varies monotonously, decreasing in planes parallel to the plane of the substrate, as the distance from the waveguide increases, the average optical index being defined as being an average value of the optical index in a cubic volume (V(x, y, z)) with a side dimension equal to:
- λ
- 0
- 2
- *
- n
- eff
- wherein neff is the effective index of guided mode in the waveguide;
- said average value being a root mean square of the optical indexes of materials forming said cubic volume, weighted by the volume proportion of each of these materials in the cubic volume.
Dependencies are inferred from the claim text.