Method for manufacturing a waveguide for generating polarization-entangled photons and waveguides

Abstract

A method for fabricating a waveguide for generating polarization-entangled photons is proposed, comprising the following steps: a) providing a support substrate (2). b) applying a layer of a nonlinear material to the support substrate (2). The waveguide (1) spans a Cartesian coordinate system with axes x, y, and z. In step b), the layer of nonlinear material is applied in the y-direction, starting from the support substrate (2). The waveguide (1) forms a propagation direction in the z-direction and, perpendicular to this, a cross-section in the x- and y-directions. The nonlinear material is non-centrosymmetric. The nonlinear material exhibits a second-order susceptibility that forms a 3x3x3 tensor jijk(2) in the coordinate system of the waveguide (1), where the propagation indices i, j, k take on x, y, or z, respectively. It holds true that &khgr;xxy(2)=&khgr;xyx(2) and &khgr;yxy(2)=&khgr;yyx(2).Furthermore, either min(|&khgr;xxy(2)|,|&khgr;yxx(2)|)>max(|&khgr;xxx(2)|,|&khgr;yxy(2)|) or min(|&khgr;xyy(2)|,|&khgr;yxy(2)|)>max(|&khgr;xxy(2)|,|&khgr;yyy(2)|). A corresponding waveguide (1) for generating polarization-entangled photons is also proposed.

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