Patent ID: 7616854

Claim:
An apparatus, comprising: an optical coupling structure disposed proximate a planar waveguide and within a low refractive index cladding region, whereinthe optical coupling structure includes a first guiding portion and a second guiding portion; the first guiding portion having a first end proximate a core of the planar waveguide and having a first width, and a secondend proximate the second guiding portion and having a second width, wherein the second end of the first guiding portion has a first thickness; and the second guiding portion having a first end adjacent to the second end of the first guiding portion and having a third width, and a second end having a fourth width, wherein the second end of the second guiding portion has a second thickness less than the firstthickness, and further wherein the second width is less than the third width at a point where the first and second guiding portions encounter one another, wherein the second guiding portion is end-coupleable to a single mode optical fiber and a cross-sectional area of the second end of the second guiding portion is less than about 1 percent of a cross-sectional area of a core of the single mode optical fiber to which the second guiding portion is end-coupleable.