Patent ID: 6999660
Filing Date: 2006-02-14
Classification: G02B

Abstract:
1. A focusing waveguide grating coupler using a leaky mode, comprising: a substrate having a first refractive index n1; a first core layer having a second refractive index n2, the first core layer being formed on the substrate; a second core layer having a third refractive index n3, the second core layer being formed on the first core layer apart from the first core layer with a space d in between; a first cladding layer having a fourth refractive index n4, the first cladding layer being formed on the second core layer; a second cladding layer having a fifth refractive index n5, the second cladding layer being formed on the first cladding layer and inserted between the first core layer and the second core layer; and a Fresnel lens positioned on the second cladding layer, wherein the refractive indexes satisfy conditions of n5>(n2, n3)>n1 and n5>n4; and light inputted through the first and second core layers propagates to the Fresnel lens as radiated leaky beams by a leaky mode formed according to the conditions, and the leaky beams form an optical focus by performing single directional coupling towards the lower part of the substrate by using beams reflected from the Fresnel lens.